Official solved question paper for Birla Institute of Technology and Science Admission Test. Review all 130 questions, official answer keys, and detailed step-by-step solutions below, or attempt online with timer and negative marking.
He gave a large amount of donation for flood victims and everyone appreciated his magnanimous act.
A
Vindiative
B
Chimerical
C
Chivalrous
D
Cherubic
Official Correct Answer:Option (C)
Step-by-Step Solution:
To determine the best word that expresses the meaning of the underlined word "magnanimous" in the sentence, we need to understand the definition of "magnanimous."
The word "magnanimous" means generous or noble, especially in forgiving or giving. A magnanimous person shows a lofty and courageous spirit. In the given sentence, the context indicates an act of giving a large amount for flood victims, which aligns with the characteristic of being generous or noble.
Let's evaluate the options:
Option A: Vindictive
"Vindictive" means having or showing a strong or unreasoning desire for revenge. It does not align with the context of generosity.
Option B: Chimerical
"Chimerical" refers to something that is imaginary or fantastical. This option is also not relevant to the concept of generosity or nobility.
Option C: Chivalrous
"Chivalrous" means being courteous, respectful, and gallant, especially towards women. It also encompasses qualities like bravery and honor, which can be related to nobility and generosity.
Option D: Cherubic
"Cherubic" describes something that resembles a cherub, typically characterized by an innocent and angelic appearance. This term does not fit the context of generosity.
In conclusion, the best word that expresses the meaning of "magnanimous" in this context is Option C: Chivalrous.
Q 2englishSection A • MCQrearrangement
+3 / -1
A. There are other who claim that they have never been so well connected.
B. However, such social networking sites help us to keep in touch with old friends or make new ones.
C. Whether or not Facebook friendships are lasting is debatable.
D. Some people believe that real friendships are collapsing in modern times.
A
DACB
B
CBAD
C
CDBA
D
DBCA
Official Correct Answer:Option (C)
Step-by-Step Solution:
The correct order of the sentences is Option C: CDBA. Here's why:
C. Whether or not Facebook friendships are lasting is debatable. This sentence introduces the topic of Facebook friendships and their longevity, setting the stage for the following sentences.
D. Some people believe that real friendships are collapsing in modern times. This sentence presents one side of the debate, arguing that real friendships are declining.
B. However, such social networking sites help us to keep in touch with old friends or make new ones. This sentence provides a counterargument to the previous one, highlighting the positive aspects of social networking sites.
A. There are others who claim that they have never been so well connected. This sentence further supports the counterargument by stating that people feel more connected than ever before.
Therefore, the order CDBA creates a coherent paragraph that presents both sides of the argument about Facebook friendships and their impact on real-life connections.
Q 3englishSection A • MCQrearrangement
+3 / -1
A. Most of these superpowers are not rich in natural resources and have faced political turmoil.
B. Human capital ultimately makes the difference, both in an enterprise and a nation
C. the new economic superpowers of today amply testify this thesis.
D. Yet, they have achieved economic affluence in a relatively short period.
A
BCDA
B
ADBC
C
ACDB
D
BCAD
Official Correct Answer:Option (D)
Step-by-Step Solution:
The correct order of the sentences is Option D: BCAD.
Here's the explanation:
B. This sentence introduces the main topic: the importance of human capital. It sets the stage for the following sentences.
C. This sentence provides evidence to support the claim in sentence B, stating that "new economic superpowers" are a testament to the power of human capital.
A. This sentence further elaborates on the superpowers mentioned in sentence C, highlighting that they aren't naturally resource-rich and have experienced political difficulties.
D. Finally, this sentence concludes by emphasizing the remarkable achievement of these superpowers in achieving economic success despite these challenges.
Therefore, the order BCAD creates a logical flow, starting with the general point about human capital, then providing examples, and finally explaining the context and achievement of those examples.
Q 4englishSection A • MCQvocabulary
+3 / -1
Critical explanation or interpretation of a text, especially of scripture
A
Oblivion
B
Nascence
C
Exegesis
D
Naivete
Official Correct Answer:Option (C)
Step-by-Step Solution:
The answer to your question is Option C: Exegesis.
Exegesis refers to the critical explanation or interpretation of a text, especially of scripture. It involves an in-depth study and analysis of the text to understand its meaning and context. Scholars and theologians often perform exegesis to gain a deeper understanding of religious texts.
Here's a brief explanation of the other options for clarification:
Oblivion: This term refers to the state of being unaware or unconscious of what is happening around one. It can also mean the state of being forgotten.
Nascence: This word refers to the process of coming into existence; beginning to develop.
Naivete: This term refers to the state of being naive, which means having or showing a lack of experience, judgment, or information.
Q 5englishSection A • MCQvocabulary
+3 / -1
Culmination
A
Completion
B
Climax
C
Conclusion
D
Beginning
Official Correct Answer:Option (D)
Step-by-Step Solution:
The word "culmination" refers to the highest or climactic point of something, especially as attained after a long time. It signifies the peak or final stage of a process or event. To find the opposite in meaning, we need to consider a word that signifies the start or initial stage rather than the endpoint.
Let's analyze each option:
Option A: Completion
Completion implies finishing something, reaching the end, or the finalization. This is very similar to "culmination" and therefore, not the opposite.
Option B: Climax
Climax also denotes the peak or most intense point of something, similar to "culmination." It is not an opposite.
Option C: Conclusion
Conclusion signifies the end or last part of something. This word also closely aligns with "culmination" and is not its opposite.
Option D: Beginning
Beginning means the start or initial point of something. This is opposite in meaning to culmination, which denotes the end or peak.
Therefore, the word opposite in meaning to "culmination" is Option D: Beginning.
Q 6englishSection A • MCQvocabulary
+3 / -1
Wither
A
Shine
B
Bloom
C
Excel
D
Wilt
Official Correct Answer:Option (B)
Step-by-Step Solution:
The word "wither" means to dry up or shrivel, often used in the context of plants losing vitality and freshness. Therefore, we need to choose a word that conveys the opposite meaning, indicating growth, vitality, or flourishing.
Let's examine the options:
Option A: Shine - This word means to emit light or glow and is not directly related to the vibrancy of plants.
Option B: Bloom - This word means to produce flowers, to flourish, or thrive. It represents the exact opposite sense of withering.
Option C: Excel - This word means to do exceptionally well in a particular area and is, again, not related to the context of plants withering.
Option D: Wilt - This word is a synonym for wither as it also means to lose freshness and vitality.
Thus, the word opposite in meaning to "wither" is:
Option B: Bloom
Q 7englishSection A • MCQgrammar
+3 / -1
Select the one which best expresses the same sentence in Passive/Active voice.
Did everybody miss the first bus?
A
The first bus was missed by everybody?
B
Was the first bus missed by everybody?
C
Everybody missed the first bus?
D
Had the first bus been missed by everybody?
Official Correct Answer:Option (B)
Step-by-Step Solution:
The given sentence "Did everybody miss the first bus?" is in active voice. To change it into passive voice, we need to make the object of the verb (the first bus) the subject of the sentence, and use the appropriate form of the verb "to be" along with the past participle of the main verb (miss).
Let's analyze the options:
Option A: The first bus was missed by everybody?
This option is in passive voice, but the sentence structure is incorrect. It should be a question, which requires an inversion of the subject and auxiliary verb.
Option B: Was the first bus missed by everybody?
This option is correct. It correctly inverts the auxiliary verb "was" and the subject "the first bus," making it a proper question in passive voice.
Option C: Everybody missed the first bus?
This option is in active voice and is essentially restating the original sentence without the question format being clear.
Option D: Had the first bus been missed by everybody?
This option is in passive voice, but it changes the tense to past perfect, which doesn't match the original simple past tense of the sentence.
Therefore, the correct option that best expresses the same sentence in passive voice is:
Option B: Was the first bus missed by everybody?
Q 8englishSection A • MCQvocabulary
+3 / -1
The discovery of treasure under the Bermuda Triangle is probably a hoax.
A
Analogy
B
Delusion
C
Bonanza
D
Trick
Official Correct Answer:Option (D)
Step-by-Step Solution:
To determine which word best expresses the meaning of the underlined word "hoax" in the sentence "The discovery of treasure under the Bermuda Triangle is probably a hoax," it is important to understand what "hoax" means.
A "hoax" is a deliberate deception made to trick people into believing something that is not true. Therefore, we need a synonym that captures this sense of deception and trickery.
Let's analyze the options:
Option A: Analogy
An analogy is a comparison between two things, typically for the purpose of explanation or clarification. This does not capture the essence of deception or trickery.
Option B: Delusion
A delusion is a false belief or judgment about external reality, held despite proof or evidence to the contrary. While it is somewhat related to false belief, it does not specifically imply intentional deception.
Option C: Bonanza
A bonanza is a situation or event that creates a sudden increase in wealth, good fortune, or profits. This is the opposite of a hoax and does not fit at all.
Option D: Trick
A trick is an action that is intended to deceive someone. This is directly aligned with the meaning of "hoax," making it the best choice.
Therefore, the word which best expresses the meaning of the underlined word "hoax" is:
Option D: Trick
Q 9englishSection A • MCQcomprehension ability
+3 / -1
Select the sentence that means same as the given sentence. Sohan was too weak to play.
A
Sohan was so weak that he could not play.
B
Sohan was as weak as he could not play.
C
Sohan was very weak because he could not play.
D
Sohan was so weak as he could not play.
Official Correct Answer:Option (A)
Step-by-Step Solution:
The sentence "Sohan was too weak to play" implies that Sohan's weakness prevented him from playing. The structure "too...to..." indicates an excessive degree of weakness that stops him from engaging in the activity of playing. Now, let's analyze the given options:
Option A: Sohan was so weak that he could not play.
This option essentially means the same thing as the original sentence. It conveys that Sohan's level of weakness prevented him from playing. The use of "so...that..." effectively translates the meaning of "too...to...". Hence, Option A is correct.
Option B: Sohan was as weak as he could not play.
This sentence is structurally incorrect and does not convey the same meaning as the original sentence. The phrase "as weak as" is not appropriately followed by the clause "he could not play".
Option C: Sohan was very weak because he could not play.
This sentence implies that Sohan's weakness is a result of his inability to play, which is the opposite of the original meaning. The original sentence means his weakness prevented him from playing, not the other way around.
Option D: Sohan was so weak as he could not play.
Similar to Option B, this sentence is grammatically incorrect and does not convey the same meaning as the original sentence. The structure "so...as" is not used correctly here.
Therefore, the correct option is Option A: Sohan was so weak that he could not play.
Q 10englishSection A • MCQvocabulary
+3 / -1
Destruction or slaughter on a mass scale.
A
Enshrine
B
Cenotaph
C
Opulent
D
Holocaust
Official Correct Answer:Option (D)
Step-by-Step Solution:
Holocaust is a situation in which there is great destruction and a lot of people die. So, it is the best substitute for the words.
Q 11logical-reasoningSection A • MCQdirection sense test
+3 / -1
Six friends, A, B, C, D, E and F are sitting around a circular table facing the centre of the table. A is to the immediate left of E. B is to the immediate right of F. D is second to the left of F. A and C have equal number of persons between them from both the ends. Who is sitting between A and F ?
A
D
B
E
C
B
D
C
Official Correct Answer:Option (C)
Step-by-Step Solution:
Accounting to the given information, the arrangement is as follow,
So, it is clear 'B' is sitting between A and F.
Q 12logical-reasoningSection A • MCQanalogy
+3 / -1
Select the word-pair in which the two words are related in the same way as are the two words in the following word-pair.
Growth : Expansion
A
Child : Birth
B
Urge : Request
C
First : Last
D
Temporary : Permanent
Official Correct Answer:Option (B)
Step-by-Step Solution:
To understand the relationship between "Growth" and "Expansion," let's break down the pair. "Growth" refers to the process of increasing in size, quantity, or significance, while "Expansion" refers to the process of something becoming larger or more extensive. Therefore, the relationship can be summarized as a cause and effect or state that follows from an initial state.
Now, let's evaluate each option to identify which one shares a similar relationship:
Option A: Child : Birth
The relationship here can be described as the origin or commencement. A "Child" is the result or outcome of "Birth." This relationship, however, is not exactly similar to growth leading to expansion but rather an origin-result relationship.
Option B: Urge : Request
This relationship describes a situation where an "Urge" (a strong desire or impulse) can lead to a "Request" (an act of asking for something). This is quite similar to the cause-effect relationship seen in Growth leading to Expansion.
Option C: First : Last
This relationship is one of sequential order, where "First" and "Last" represent the beginning and ending points in a series. This does not match the growth-expansion relationship, which is transformational rather than positional.
Option D: Temporary : Permanent
This relationship is one of contrast, where "Temporary" means lasting for a limited period and "Permanent" means lasting indefinitely. This does not fit the pattern of growth leading to expansion.
Given the options, the correct word-pair that shares a similar relationship to "Growth" and "Expansion" is:
Option B: Urge : Request
Q 13logical-reasoningSection A • MCQdirection sense test
+3 / -1
Two different positions of the same dice are shown below. Select the number that will be at the top if ' 6 ' is at the bottom.
A
4
B
5
C
2
D
3
Official Correct Answer:Option (D)
Step-by-Step Solution:
Here, 1 is common and it is on the same face in both the positions. So, 4 and 2 are opposite, 6 and 3 are opposite. Hence, 3 will be at the top if 6 is at the bottom.
Q 14logical-reasoningSection A • MCQmirror image
+3 / -1
Select the correct mirror image of the given combination when the mirror is placed at MN as shown below.
A
B
C
D
Official Correct Answer:Option (B)
Step-by-Step Solution:
The correct mirror image of the given combination is,
Q 15logical-reasoningSection A • MCQlogical deduction
+3 / -1
Statement The old order changed yielding place to new
Conclusions
I. Change is the law of nature.
II. Discard old ideas because they are old.
A
Only Conclusion I follows
B
Only Conclusion II follows
C
Either I or II follows
D
Both I and II follow
Official Correct Answer:Option (A)
Step-by-Step Solution:
To determine which conclusions definitely follow from the given statement, let's analyze each conclusion in detail.
Statement: The old order changed yielding place to new
This statement implies that there is a process where old systems or ideas are being replaced by new ones.
Conclusion I: Change is the law of nature.
This conclusion is a broad generalization stating that change is a fundamental principle of the natural order. The statement supports this idea by illustrating an example of change (the old order making way for new). Thus, Conclusion I follows from the statement.
Conclusion II: Discard old ideas because they are old.
This conclusion implies that ideas should be discarded merely because they are old. The statement does not provide sufficient information to support the notion that "old ideas should be discarded only due to their age." It merely indicates that the old order changes to make way for something new but does not necessarily suggest discarding ideas solely because of their age.
Based on this analysis, it is clear that:
Option A: Only Conclusion I follows.
Q 16logical-reasoningSection A • MCQseries completion
+3 / -1
Which letter-cluster will replace the question mark (?) in the given series?
KLIMC, JJFIX, IHCES, HFZAN, ?
A
HEWWI
B
GDUVI
C
GDWWI
D
GDXWJ
Official Correct Answer:Option (C)
Step-by-Step Solution:
The pattern of the series is as follow,
So, 'GDWWI' will replace the question mark.
Q 17logical-reasoningSection A • MCQpaper folding and cutting
+3 / -1
A paper is folded and cut as shown below. How will it appear when unfolded?
A
B
C
D
Official Correct Answer:Option (C)
Step-by-Step Solution:
It will appear when unfolded like as,
Q 18logical-reasoningSection A • MCQclassification
+3 / -1
Four options have been given, out of which three are alike in some manner and one is different. Select the option that is different.
A
Delhi
B
Puducherry
C
Chandigarh
D
Jammu and Kashmir
Official Correct Answer:Option (C)
Step-by-Step Solution:
Chandigarh is the capital of two states Haryana and Punjab.
∴ Chandigarh is different from others.
Q 19logical-reasoningSection A • MCQanalogy
+3 / -1
Flourine is related to Halogen in the same way as Helium is related to _________.
A
inert gas
B
gas
C
radio active
D
metal
Official Correct Answer:Option (A)
Step-by-Step Solution:
The correct answer is Option A: inert gas. Here's why:
The question is asking about the relationship between elements based on their position in the periodic table.
Flourine (F) is a member of the halogen group (Group 17). Halogens are highly reactive nonmetals.
Helium (He) is a member of the noble gas group (Group 18). Noble gases are known for being extremely unreactive, hence the name "inert gases."
So, the relationship is that both Flourine and Helium are in the same column of the periodic table, indicating they share similar chemical properties.
Let's look at why the other options are incorrect:
Option B: Gas: While both Fluorine and Helium are gases at room temperature, this is not the specific relationship the question is looking for. Many elements are gases.
Option C: Radioactive: Neither Fluorine nor Helium are inherently radioactive. Some isotopes of these elements may be radioactive, but that's not the primary characteristic defining their groups.
Option D: Metal: Both Fluorine and Helium are nonmetals.
Q 20logical-reasoningSection A • MCQlogical deduction
+3 / -1
Among five persons P, Q, R, S and T, T is older than P,Q is younger than T,S is older than R and P is older than S but younger than Q. Who is the oldest among all?
A
P
B
T
C
S
D
Q
Official Correct Answer:Option (B)
Step-by-Step Solution:
Let's analyze the given information step by step to determine the ages of P, Q, R, S, and T relative to each other:
1. T is older than P.
This means T>P.
2. Q is younger than T.
This means T>Q.
3. S is older than R.
This means S>R.
4. P is older than S but younger than Q.
This means Q>P>S.
Now let's combine these relationships to form an order:
From (1) and (2), we have: T>Q.
From (4), we have: Q>P>S.
From (3), we have: S>R.
Combining all the information, we get:
T>Q>P>S>R.
Therefore, the oldest among all is T.
Correct Answer: Option B - T
Q 21logical-reasoningSection A • MCQfigure formation
+3 / -1
Select the option that is not embedded in the given figure as its part (rotation is not allowed).
A
B
C
D
Official Correct Answer:Option (A)
Step-by-Step Solution:
Option figure (a) is not embedded in the given figure as its part.
Q 22logical-reasoningSection A • MCQseries completion
+3 / -1
Which number will replace the question mark (?) in the given series?
61,73,99,141,201,?
A
281
B
261
C
269
D
244
Official Correct Answer:Option (A)
Step-by-Step Solution:
The pattern of the series is as follows,
Hence, 281 will replace the question mark.
Q 23logical-reasoningSection A • MCQanalogy
+3 / -1
Select the option in which the numbers are related in the same way as are the numbers of the following set.
29:36:39
A
48:52:55
B
54:58:61
C
69:72:76
D
78:79:82
Official Correct Answer:Option (A)
Step-by-Step Solution:
Q 24logical-reasoningSection A • MCQseries completion
+3 / -1
Select the figure that will replace the question mark (?) in the following figure series.
A
B
C
D
Official Correct Answer:Option (A)
Step-by-Step Solution:
On observing the given pattern, the arrow moving 90∘ in clockwise direction along with the pointed shape in each step. So, figure of option (a) will replace the question mark.
Q 25logical-reasoningSection A • MCQfigure matrix
+3 / -1
How many triangles are there in the following figure?
A
24
B
19
C
26
D
22
Official Correct Answer:Option (C)
Step-by-Step Solution:
Given,
There are 26 triangles in the given figure, they are △ABK,△BKC,△ABC,△DCL,△DEL,△CDE,△AJK,△KJC,△AJC,△CJL,△LJE,△CJE,△ACE,△HGI,△GIF,△HGF,△AGJ,△EGJ,△AGE,△AGC,△ECG,△JCD,△JED,△ABJ,△BJC and △BJD.
Q 26logical-reasoningSection A • MCQlogical deduction
+3 / -1
Statement In a one day cricket match, the total runs made by a team were 200. Out of these, 160 runs were made by spinners.
Conclusions
I. 80% of the team consists of spinners.
II. The opening batsmen were spinners.
A
Only Conclusion I follows
B
Only Conclusion II follows
C
Neither I nor II follows
D
Both I and II follow
Official Correct Answer:Option (C)
Step-by-Step Solution:
To analyze whether the given conclusions follow from the statement, let's carefully examine the statement and each conclusion individually.
Statement: In a one-day cricket match, the total runs made by a team were 200. Out of these, 160 runs were made by spinners.
Conclusion I:80% of the team consists of spinners.
This conclusion points out a percentage related to the team composition. However, the statement only talks about the runs made by spinners and does not provide any direct information about what percentage of the team members are spinners. Therefore, we cannot conclusively determine the team composition based only on the runs scored.
Conclusion II: The opening batsmen were spinners.
This conclusion assumes that the opening batsmen were spinners based on the runs scored. The statement, however, does not provide any information about who were the opening batsmen - it only mentions the total and specific runs scored by spinners. Therefore, this conclusion cannot be definitively drawn from the given statement.
We see that neither conclusion I nor conclusion II can be conclusively derived from the given statement.
Answer: Option C: Neither I nor II follows.
Q 27logical-reasoningSection A • MCQanalogy
+3 / -1
Select the number that is related to the third number in the same way as the second number is related to the first number.
12:36::18: ?
A
64
B
48
C
83
D
81
Official Correct Answer:Option (D)
Step-by-Step Solution:
The pattern is follow as,
As, 12:36=4(12)2=36
Similarly, 18:81=4(18)2=81
So, the required number is 81.
Q 28logical-reasoningSection A • MCQrule detection
+3 / -1
In a code language, if 'FORTUNE' is written as '716192122156', then how will 'OCTOBER' be written in the same language?
A
16420173819
B
16421163619
C
14422163519
D
1532063618
Official Correct Answer:Option (B)
Step-by-Step Solution:
As,
Q 29logical-reasoningSection A • MCQblood relations
+3 / -1
'A # B' means 'A is the husband of B'.
'A @ B' means 'A is the daughter of B'.
'A & B' means 'A is the sister of B'.
If 'P & Q @ D # K @ S # T', then which of the following statements is not correct?
A
S is the maternal grandfather of Q
B
P is the daughter of K
C
T is the mother of K
D
D is the daughter-in-law of T
Official Correct Answer:Option (D)
Step-by-Step Solution:
Given,
# - Husband, @ - Daughter
& - Sister
We have,
P&Q@D#K@S#T
Here, in option (d), D is the daughter-in-law of 'T' is not a correct statement.
Q 30logical-reasoningSection A • MCQlogical deduction
+3 / -1
₹ 5110 is to be divided among Rajesh, Vivek and Kripal in such a way that Rajesh gets double the amount that Vivek gets and Kripal gets double the amount that Rajesh gets. How much money will Kripal get?
A
₹ 2920
B
₹ 2188
C
₹ 1550
D
₹ 2236
Official Correct Answer:Option (A)
Step-by-Step Solution:
Let's denote the amounts received by Rajesh, Vivek, and Kripal as R, V, and K respectively.
According to the problem, Rajesh gets double the amount that Vivek gets, so we have:
R=2V
Similarly, Kripal gets double the amount that Rajesh gets, so we have:
K=2R
The total amount to be divided is ₹ 5110. Therefore, we can write the equation:
R+V+K=5110
Substitute R and K in terms of V from the above equations:
R=2V
K=2R=2(2V)=4V
Now substitute these into the total amount equation:
2V+V+4V=5110
Simplify the equation:
7V=5110
Solve for V:
V=75110=730
Now, calculate the amounts received by Rajesh and Kripal:
R=2V=2×730=1460
K=4V=4×730=2920
So, the amount of money Kripal will get is ₹ 2920.
Therefore, the correct option is Option A: ₹ 2920.
Q 31MathematicsSection A • MCQdifferential equations
+3 / -1
If (1+x2)dy+2xydx=cotxdx, then the general solution be
A
y=1+x2log∣sinx∣+1+x2C
B
y=1−x2log∣sinx∣+1−x2C
C
y=1+x2log∣cosx∣+1+x2C
D
y=1−x2log∣cosx∣+1−x2C
Official Correct Answer:Option (A)
Step-by-Step Solution:
Given, (1+x)2dy+2xydx=cotxdx
⇒dxdy+1+x22xy=1+x2cotx,
which is a linear differential equation of the form of dxdy+Py=Q
Here, P=1+x22x and Q=1+x2cotx
Now, IF =exp(∫1+x22xdx)=exp(log(1+x2))
=1+x2
and the solution of this linear differential equation be
Q 32MathematicsSection A • MCQtrigonometric ratios and identities
+3 / -1
A tower T1 of the height 60m is located exactly opposite to a tower T2 of height 80m on a straight road. From the top of T1, if the angle of depression of the foot of T2 is twice the angle of elevation of the top of T2, then the width (in m) of the road between the feet of the towers T1 and T2 is
A
203
B
103
C
102
D
202
Official Correct Answer:Option (A)
Step-by-Step Solution:
Let AE be the tower T2 of height 80m and BC be the tower T1 of height 60m. Let AB=CD=hm
In △EDC,
CDED=tanx⇒h20=tanx⇒h=tanx20.... (i)
In △ABC,ABBC=tan2x⇒h60=tan2x⇒h60=1−tan2x2tanx⇒h30=1−tan2xtanx⇒h=tanx30(1−tan2x)... (ii)
From Eqs. (i) and (ii), we get
tanx30(1−tan2x)=tanx20⇒3−3tan2x=2⇒tan2x=31⇒tanx=±31⇒x=6π or 65π
So, on putting the value of x in Eq. (i), we get
h=tan(6π)20 or h=203m
Q 33MathematicsSection A • MCQcomplex numbers
+3 / -1
If z1 and z2 be nth root of unity which subtend a right angled at the origin. Then, n must be of the form
A
4K+1
B
4k
C
4k+2
D
4k+3
Official Correct Answer:Option (B)
Step-by-Step Solution:
Let z=(1)1/n=(cos2kπ+isin2kπ)1/n⇒z=(n2kπ)+isin(n2kπ),k=0,1,2…,n−1 Let z1=cos(n2k1π)+isin(n2k1π) and z2=cos(n2k2π)+isin(n2k2π)
be the two value of z such that they subtend right angle at origin.
∴n2k1π−n2k2π=±2π⇒4(k1−k2)=±n
As, k1 and k2 are integer and k1=k2
∴n=4k,k∈I
Q 34MathematicsSection A • MCQfunctions
+3 / -1
If f(x)=x2−2x+1 and f∘g(x)=x2+2x+1, then g(x) is equal to
Q 35MathematicsSection A • MCQapplication of derivatives
+3 / -1
Water is being filled at the rate of 1cm3/s in a right circular conical vessel (vertex downwards) of height 35cm and diameter 14cm. When the height of the water levels is 10cm, the rate (in cm2/sec) at which the wet conical surface area of the vessel increases is
If a tangent to the circle x2+y2=1 intersect the co-ordinate axes at distinct points P and Q, then the locus of the mid-point of PQ is
A
x2+y2−2xy=0
B
x2+y2−2x2y2=0
C
x2+y2−4x2y2=0
D
x2+y2−16x2y2=0
Official Correct Answer:Option (C)
Step-by-Step Solution:
The equation of tangent to the given circle at (cosθ,sinθ) be, xcosθ+ysinθ=1
It meets the X-axis at (secθ,0) and Y-axis at (0,cosecθ) Let R(h,k) be the mid-point of PQ.
∴2secθ+0=h and 20+cosecθ=k⇒2h1=cosθ... (i)
and
2k1=sinθ.... (ii)
On squaring and adding Eqs. (i) and (ii), we get
4h21+4k21=cos2θ+sin2θ
⇒41(h2k2k2+h2)=1⇒h2+k2=4h2k2⇒h2+k2−4h2k2=0
Hence, the required locus be x2+y2−4x2y2=0
Q 37MathematicsSection A • MCQcomplex numbers
+3 / -1
Number of solutions of the equation z2+∣z∣2=0 and z=0 is
A
2
B
3
C
1
D
infinitely many solutions
Official Correct Answer:Option (D)
Step-by-Step Solution:
Given, z2+∣z∣2=0,z=0
Let z=x+iy and zˉ=x−iy
⇒(x+iy)2+(x+iy)(x−iy)=0⇒x2+i2y2+i2xy+x2−i2y2=0⇒x2−y2+i2xy+x2+y2=0{∵i2=−1}⇒2x(x+iy)=0⇒x=0 or x+iy=0 (not possible) {∵zzˉ=∣z∣2}
Therefore, x=0 and y=0
So, y can take any non-zero real value.
Hence, infinitely many solutions exists.
Q 38MathematicsSection A • MCQprobability
+3 / -1
A six faced die is a biased once. It is thrice more likely to show an odd number, then show an even number. It is thrown twice. The probability that the sum of the number in two throws is odd, is
A
85
B
81
C
87
D
83
Official Correct Answer:Option (D)
Step-by-Step Solution:
Let P be the probability of getting an even number. Then, by hypothesis the probability of getting an odd number be 3P.
Since, event of getting an odd number and an even number are mutually exclusive and exhaustive.
∴3P+P=1⇒P=41
Thus, the probability of getting an odd number in a single throw is 43 and that of an even number is 41. If the die is thrown twice, then the sum of the numbers in two throws is odd if one number is odd and another is even.
∴ Required probability
=41×43+43×41=166=83
Q 39MathematicsSection A • MCQarea under the curves
+3 / -1
The area of the region bounded by the parabola y=x2+1 and lines y=x+1,y=0,x=21 and x=2 is
A
623
B
1623
C
2479
D
1679
Official Correct Answer:Option (C)
Step-by-Step Solution:
The described region is :
It is clear that
A=(21,0),B=(2,0),C=(2,3),D=(1,2)E=(21,23) and F=(21,45)
∴ Required area = Area of region A B C D E A − Area of region EDFE
\begin{aligned}
& =\frac{1}{2}\left(\frac{3}{2}+3\right)\left(2-\frac{1}{2}\right)-\int_\limits{1 / 2}^1\left[(x+1)-\left(x^2+1\right)\right] d x \\
& =\frac{1}{2} \times \frac{9}{2} \times \frac{3}{2}-\int_\limits{1 / 2}^1\left(x-x^2\right) d x \\
& =\frac{27}{8}-\left[\frac{x^2}{2}-\frac{x^3}{3}\right]_{1 / 2}^1 \\
& =\frac{27}{8}-\left[\left(\frac{1}{2}-\frac{1}{3}\right)-\left(\frac{1}{8}-\frac{1}{24}\right)\right] \\
& =\frac{27}{8}-\left(\frac{1}{6}-\frac{1}{12}\right) \\
& =\frac{27}{8}-\frac{1}{12}=\frac{79}{24}
\end{aligned}
Q 40MathematicsSection A • MCQlimits continuity and differentiability
+3 / -1
\text { The value of } \lim _\limits{x \rightarrow 0} \frac{(27+x)^{1 / 3}-3}{9-(27+x)^{2 / 3}} \text { equals to }
The equation of the line passing through (−4,3,1) parallel to the plane x+2y−z−5=0 and intersecting the line −3x+1=2y−3=−1z−2 is
A
3x+4=−1y−3=1z−1
B
−1x+4=1y−3=1z−1
C
1x+4=1y−3=3z−1
D
2x−4=1y+3=4z+1
Official Correct Answer:Option (A)
Step-by-Step Solution:
Any point on the line −3x+1=2y−3=−1z−2, is of the form (−3λ−1,2λ+3,−λ+2).
Let the point A≡(−3λ−1,2λ+3,−λ+2) and B≡(−4,3,1)
Then, AB=(3λ−3)i^−2λj^+(λ−1)k^
Now, as the line is parallel to the given plane, therefore AB will be parallel to the given plane and so AB will be perpendicular to the normal of plane.
⇒AB⋅n=0, where n=i^+2j^−k^ is normal to the plane.
Q 43MathematicsSection A • MCQproperties of triangles
+3 / -1
Let sinBsinA=sin(C−B)sin(A−C), where A,B and C are angles of a △ABC. If the lengths of the sides opposite these angles are a,b and c respectively, then
A
b2−a2=a2+c2
B
b2,c2,a2 are in AP
C
c2,a2,b2 are in AP
D
a2,b2,c2 are in AP
Official Correct Answer:Option (B)
Step-by-Step Solution:
Given, sinBsinA=sin(C−B)sin(A−C)⇒sin(A+C)sin(B+C)=sin(C−B)sin(A−C)[∵A+B+C=π and sin(π−θ)=sinθ]⇒sin(B+C)sin(C−B)=sin(A+C)sin(A−C)⇒sin2C−sin2B=sin2A−sin2C⇒2sin2C=sin2A+sin2B⇒2(2RsinC)2=(2RsinA)2+(2RsinB)2⇒2c2=a2+b2[∵sinAa=sinBb+sinCc=2R]⇒a2,c2,b2 are in AP. ⇒b2,c2,a2 are in AP.
Q 44MathematicsSection A • MCQstatistics
+3 / -1
The mean and variance of the data 4,5,6,6,7,8,x,y, where x<y are 6 and 49, respectively.
Then, x2−2y is equal to
A
8
B
32
C
0
D
4
Official Correct Answer:Option (C)
Step-by-Step Solution:
Given, mean =6 and variance =49
∴84+5+6+6+7+8+x+y=6
⇒⇒36+x+y=48x+y=12... (i)
And
81(42+52+62+62+72+82+x2+y2)−62=49
⇒⇒81(226+x2+y2)=4153x2+y2=80... (ii)
On solving Eqs. (i) and (ii), we get
x∴x2−2y=4 and y=8[∵x<y]=(4)2−2(8)=16−16=0
Q 45MathematicsSection A • MCQtrigonometric ratios and identities
+3 / -1
If A,B,C∈[0,π] and if A,B,C are in AP, then cosA+cosCsinA+sinC is equal to
A
sinB
B
cosB
C
cotB
D
tanB
Official Correct Answer:Option (D)
Step-by-Step Solution:
Given that A,B,C∈[0,π] and A,B,C are in Arithmetic Progression (AP), we know the following:
If three angles are in AP, the middle angle is the arithmetic mean of the other two. Therefore, we can represent:
B=2A+C
We need to find the value of the expression cosA+cosCsinA+sinC.
Using the sum-to-product identities, we have:
sinA+sinC=2sin(2A+C)cos(2A−C)
And
cosA+cosC=2cos(2A+C)cos(2A−C)
Substituting these identities into the given expression, we get:
Q 49MathematicsSection A • MCQsequences and series
+3 / -1
Given, a sequence of 4 numbers, first three of which are in GP and the last three are in AP with common difference 6. If first and last term of this sequence are equal, then the last term is
A
4
B
2
C
8
D
16
Official Correct Answer:Option (C)
Step-by-Step Solution:
Let a,b,c and d be four numbers of sequence.
Now, according to the question, b2=ac and c−b=d−c=6
Since a and b are positive, r=34 is the suitable solution.
Now calculate values for a and b:
a=161⋅34=121
b=(121)⋅34=91
Finally,72(a+b) =:
72(121+91)=72(363+4)=72(367)=14
Therefore, the answer is Option B: 14.
Q 53MathematicsSection A • MCQtrigonometric equations
+3 / -1
If n is the number of solutions of the equation 2cosx(4sin(4π+x)sin(4π−x)−1)=1,x∈[0,π] and S is the sum of all these solutions, then the ordered pair (n,S) is
Q 54MathematicsSection A • MCQarea under the curves
+3 / -1
Let the functions f:R→R and g:R→R be defined by f(x)=ex−1−e−∣x−1∣ and g(x)=21(ex−1+e1−x). Then, the area of the region in the first quadrant bounded by the curves ' in math mode at position 15: y=f(x), y=g(x)̲ and x=0" style="color:#cc0000">y=f(x), y=g(x) and $x=0 is.
A
(2−3)+21(e−e−1)
B
(2+3)+21(e−e−1)
C
(2−3)+21(e+e−1)
D
(2+3)+21(e+e−1)
Official Correct Answer:Option (A)
Step-by-Step Solution:
Given, f(x)=ex−e−∣x−1∣
∴f(x)={0ex−1−e1−x if x<1, if x≥1}
The graph of f and g can be plotted in the first quadrant as given below.
The point of intersection, A is given by f(x)=g(x)
\begin{aligned}
& \Rightarrow \quad e^{x-1}-e^{1-x}=\frac{1}{2}\left(e^{x-1}+e^{1-x}\right) \\
& \Rightarrow \quad e^{x-1}=3 e^{1-x} \\
& \Rightarrow \quad\left(e^{x-1}\right)^2=3 \Rightarrow e^{2 x-2}=3 \\
& \Rightarrow \quad 2 x-2=\ln 3 \\
& \Rightarrow \quad x=1+\frac{1}{2} \ln 3 \\
& \therefore \text { Required area }=\int_\limits0^1\left(\frac{1}{2} e^{x-1}+e^{1-x}\right) d x +\int_\limits1^{1+\frac{1}{2} \ln 3}\left[\left(\frac{1}{2} e^{x-1}+e^{1-x}\right)-\left(e^{x-1}-e^{1-x}\right)\right] d x
\end{aligned}
Q 58MathematicsSection A • MCQapplication of derivatives
+3 / -1
A cylindrical tank of radius 10m is being filled with wheat at the rate of 200π cubic metre per hour. Then, the depth of the wheat is increasing at the rate of
Q 60MathematicsSection A • MCQmatrices and determinants
+3 / -1
If a,b,c are non-zero real numbers and if the system of equations (a−1)x−y−z=0,−x+(b−1)y−z=0,−x−y+(c−1)z=0 has a non-trivial solution, then ab+bc+ca equals to
A
abc
B
a+b+c
C
1
D
−1
Official Correct Answer:Option (A)
Step-by-Step Solution:
Given, system of equations has a non-trivial solution
Q 61MathematicsSection A • MCQmatrices and determinants
+3 / -1
If the system of linear equation 3x−2y+z=2,4x−3y+3z=−5 and 7x−5y+λz=9 has no solution, then λ equals to
A
4
B
5
C
6
D
7
Official Correct Answer:Option (A)
Step-by-Step Solution:
To determine the value of λ for which the given system of linear equations has no solution, we need to analyze the consistency of these equations. The given system is:
3x−2y+z=2 (Equation 1)
4x−3y+3z=−5 (Equation 2)
7x−5y+λz=9 (Equation 3)
For a system of linear equations to have no solution, the equations must be inconsistent, meaning they do not intersect at any point. This happens when the determinant of the coefficient matrix is zero, and the augmented matrix creates a contradiction.
First, let's form the coefficient matrix and calculate its determinant. The coefficient matrix A of the system is:
A=347−2−3−513λ
The determinant of matrix A is given by:
det(A)=347−2−3−513λ
Expanding this determinant along the first row, we get:
det(A)=3−3−53λ−(−2)473λ+147−3−5
Now, calculate these 2x2 determinants:
−3−53λ=(−3)(λ)−(3)(−5)=−3λ+15
473λ=(4)(λ)−(3)(7)=4λ−21
47−3−5=(4)(−5)−(−3)(7)=−20+21=1
Substitute these into the expansion to get the determinant:
det(A)=3(−3λ+15)+2(4λ−21)+1(1)
=3(−3λ+15)+2(4λ−21)+1
=3(−3λ)+3(15)+2(4λ)−2(21)+1
=−9λ+45+8λ−42+1
=−λ+4
For the system to have no solution, det(A) must be zero, because that's when the coefficient matrix does not have full rank and the system is inconsistent:
−λ+4=0
λ=4
Therefore, the value of λ that makes the system of linear equations have no solution is 4.
Answer: (A) 4
Q 62MathematicsSection A • MCQcircle
+3 / -1
If the straight line y=mx+c, touches the circle x2+y2=a2 at a point, then c2 is
0x=3y=−3z=λ⇒x=0,y=3λ and z=−3λ But, ∣c∣=1⇒x2+y2+z2=1⇒9λ2+9λ2=1⇒λ=±321∴c=±21(−j^+k^)
Thus, we have c=21(−j^+k^)
Q 65MathematicsSection A • MCQsets and relations
+3 / -1
If A={x:x is a multiple of 8} and B={x:x is a multiple of 12}, then A∩B consists of multiple of
A
96
B
20
C
4
D
24
Official Correct Answer:Option (D)
Step-by-Step Solution:
To determine the set A∩B, which represents the common elements between sets A and B, we need to find the multiples of both 8 and 12. In other words, we need to find the least common multiples (LCM) of 8 and 12.
First, let's find the prime factorization of 8 and 12:
- 8 can be factored into prime numbers as: 8=23
- 12 can be factored into prime numbers as: 12=22⋅3
To find the LCM, we take the highest power of each prime that appears in these factorizations. Thus, the LCM of 8 and 12 is:
LCM(8,12)=23⋅3=8⋅3=24
Therefore, the multiples of 8 and 12 are common multiples of 24. Consequently, the set A∩B, which consists of numbers that are multiples of both 8 and 12, consists of multiples of 24.
The correct option is:
Option D: 24
Q 66MathematicsSection A • MCQsequences and series
+3 / -1
If a1,a2,…,an are in HP, then the expression a1a2+a2a3+…+an−1an is equal to
Q 67MathematicsSection A • MCQtrigonometric ratios and identities
+3 / -1
The upper (43) th portion of a vertical pole subtends an angel tan−1(53) at a point in the horizontal plane through its foot and at a distance 40m from the foot. A possible height of the vertical is
A
80 m
B
20 m
C
40 m
D
60 m
Official Correct Answer:Option (C)
Step-by-Step Solution:
Here, from the figure, we see that θ2=tan−153
⇒tanθ2=53.... (i)
In △AOC,tanθ1=AOAC⇒tanθ1=4041h=160h.... (ii)
And in △AOB,tan(θ1+θ2)=AOAB=40h
⇒⇒⇒⇒⇒1−tanθ1tanθ2tanθ1+tanθ2=40h1−160h×53160h+53=40hh2−200h+6400=0(h−160)(h−40)=0h=160 or h=40
Hence, height of the vertical pole is 40m.
Q 68MathematicsSection A • MCQlimits continuity and differentiability
+3 / -1
The value of \lim _\limits{x \rightarrow 0} \frac{8}{x^8}\left(1-\cos \frac{x^2}{2}-\cos \frac{x^2}{4}+\cos \frac{x^2}{2} \cos \frac{x^2}{4}\right) is
A normal is drawn at the point P to the circle x2+y2=25, which is inclined at 45∘ with the straight line y=6. Then, the point lies on the straight line
A
y=x
B
y=−x
C
y=3x
D
3y=x
Official Correct Answer:Option (A)
Step-by-Step Solution:
The normal line will makes 45∘ angle with positive X-axis because it is inclined at 45∘ with the straight line y=6 which is parallel to the X-axis.
∴ Slope of normal line =m=tan45∘=1
The centre of the circle, x2+y2=25 is (0,0).
So, the normal line will passes through (0,0), because normal line at any point P on the circle passes through its centre.
Thus, the equation of normal line be y=x and the point P lies on the straight line y=x.
Q 71ChemistrySection A • MCQthermodynamics
+3 / -1
The value of enthalpy change (ΔH) for the reaction C2H5OH(l)+3O2(g)⟶2CO2(g)+3H2O(l), at 27∘C is −1366⋅5kJmol−1. The value of internal energy change for the above reaction at this temperature will be
A
−1371.5kJmol−1
B
−1369.0kJmol−1
C
−1364.0kJmol−1
D
−1361.5kJmol−1
Official Correct Answer:Option (C)
Step-by-Step Solution:
To find the value of the internal energy change (ΔU) for the given reaction at 27∘C, we can use the relationship between enthalpy change (ΔH) and internal energy change (ΔU), given by the equation:
ΔH=ΔU+Δn⋅R⋅T
Where:
ΔH is the enthalpy change
ΔU is the internal energy change
Δn is the change in the number of moles of gas
R is the gas constant, which is 8.314Jmol−1K−1
T is the temperature in Kelvin
First, we need to determine Δn, the change in the number of moles of gas during the reaction:
For the reaction:
C2H5OH(l)+3O2(g)⟶2CO2(g)+3H2O(l)
Moles of gas on the reactant side = 3 (from O2)
Moles of gas on the product side = 2 (from CO2)
So,
Δn=moles of gas on product side−moles of gas on reactant side=2−3=−1
Now, we can convert the temperature to Kelvin:
T=27∘C+273=300K
Next, we substitute the values into the equation:
ΔH=ΔU+Δn⋅R⋅T
Here,
ΔH=−1366.5kJmol−1=−1366.5⋅103Jmol−1
Δn=−1
R=8.314Jmol−1K−1
T=300K
Solve for ΔU:
−1366.5⋅103=ΔU+(−1)⋅8.314⋅300
Simplify the equation:
−1366.5⋅103=ΔU−2494.2
So,
ΔU=−1366.5⋅103+2494.2
ΔU≈−1366.5⋅103+2.494⋅103
ΔU≈−1364.0⋅103Jmol−1
Therefore, the internal energy change ΔU is:
ΔU≈−1364.0kJmol−1
Hence, the correct option is:
Option C: −1364.0kJmol−1
Q 72ChemistrySection A • MCQelectrochemistry
+3 / -1
The equilibrium constant of the reaction
A(s)+2B+(aq)⇌A2+(aq)+2B(s)
Ecell ∘=0.0295V is [F2.303RT=0.059]
A
2×101
B
3×101
C
2×105
D
10
Official Correct Answer:Option (D)
Step-by-Step Solution:
To find the equilibrium constant Keq for the given reaction, we can use the relation between the standard cell potential Ecell∘ and the equilibrium constant. The Nernst equation at standard conditions can be written as:
Ecell∘=n0.059logKeq
Here:
Ecell∘=0.0295V
n=2 (number of electrons transferred in the balanced reaction)
F2.303RT=0.059
Now, solving for Keq:
0.0295=20.059logKeq
Multiplying both sides by 2 to isolate the logarithm term:
0.059=0.059logKeq
Dividing both sides by 0.059:
1=logKeq
Taking the antilog (base 10) of both sides:
Keq=101=10
So, the correct answer is Option D: 10.
Q 73ChemistrySection A • MCQstates of matter
+3 / -1
10g each of CH4 and O2 are kept in cylinders of same volume under same temperature, give the pressure ratio of two gases
A
3:4
B
2:3
C
1:4
D
2:1
Official Correct Answer:Option (D)
Step-by-Step Solution:
To determine the pressure ratio of the two gases, we can use the ideal gas law given by
PV=nRT
where:
P = Pressure
V = Volume
n = Number of moles
R = Universal gas constant
T = Temperature
Since the volumes and temperatures of both gases are the same, we can simplify the relationship to
P∝n
Therefore, the pressure ratio will be equal to the ratio of the number of moles of the two gases. First, we need to find the number of moles of each gas.
The number of moles is calculated as:
n=Mm
where m is the mass and M is the molar mass.
For methane, CH4:
MCH4=12+4×1=16g/mol
nCH4=16g/mol10g=0.625mol
For oxygen, O2:
MO2=2×16=32g/mol
nO2=32g/mol10g=0.3125mol
Now, we calculate the pressure ratio:
PO2PCH4=nO2nCH4=0.31250.625=2
Therefore, the pressure ratio of CH4 to O2 is 2:1.
The correct option is Option D.
Q 74ChemistrySection A • MCQionic equilibrium
+3 / -1
If the ionic product of Ni(OH)2 is 1.9×10−15, then the molar solubility of Ni(OH)2 in 1.0MNaOH is
A
2.9×10−18M
B
1.9×10−13M
C
1.9×10−15M
D
2.9×10−14M
Official Correct Answer:Option (C)
Step-by-Step Solution:
NaOH⇌(C)Na++(C)OH−
(x)Ni(OH)2⇌(x)Ni2++(x)2OH−
Total [OH−]=x+C
∴Ksp=[Ni2+][OH−]2=x(x+C)2=x(x2+2Cx+C2)
or Ksp =xC2 (neglecting higher powers of x)
⇒x=C2Ksp=(1)21.9×10−15=1.9×10−15M
Q 75ChemistrySection A • MCQsome basic concepts of chemistry
+3 / -1
If 20g of CaCO3 is treated with 100mL of 20%HCl solution, the amount of CO2 produced is
A
22.4 L
B
8.80 g
C
4.40 g
D
2.24 L
Official Correct Answer:Option (B)
Step-by-Step Solution:
Let's first write the balanced chemical equation for the reaction between calcium carbonate (CaCO3) and hydrochloric acid (HCl).
CaCO3+2HCl→CaCl2+H2O+CO2
From the equation, we can see that 1 mole of CaCO3 reacts with 2 moles of HCl to produce 1 mole of CO2.
Now, let's calculate the moles of CaCO3. The molar mass of CaCO3 is:
Molar mass ofCaCO3=40+12+3×16=100g/mol
Given that we have 20g of CaCO3, the number of moles of CaCO3 is:
Moles ofCaCO3=100g/mol20g=0.2mol
Now, let's determine the moles of HCl in the given solution. The solution is 20%HCl by weight, and we have 100mL of the solution. Assuming the density of the solution is approximately 1g/mL, we get:
Mass ofHClsolution=100mL×1g/mL=100g
Since the solution is 20%HCl, the mass of HCl is:
Mass ofHCl=20%of100g=20g
The molar mass of HCl is:
Molar mass ofHCl=1+35.5=36.5g/mol
The number of moles of HCl is:
Moles ofHCl=36.5g/mol20g≈0.548mol
The reaction requires 2 moles of HCl for 1 mole of CaCO3. Since we have only 0.2mol of CaCO3, we need:
Required moles ofHCl=0.2mol×2=0.4mol
We have more than enough HCl (0.548mol available) to fully react with 0.2mol of CaCO3.
Therefore, the amount of CO2 produced will be equal to the moles of CaCO3 reacted, which is 0.2mol.
To find the mass of CO2 produced, we use its molar mass:
Molar mass ofCO2=12+2×16=44g/mol
The mass of CO2 is:
Mass ofCO2=0.2mol×44g/mol=8.80g
The amount of CO2 produced is 8.80g.
Given the options, the correct answer is:
Option B - 8.80 g
Q 76ChemistrySection A • MCQisomerism
+3 / -1
If two compounds have the same empirical formula but different molecular formulae, they must have
A
different percentage composition
B
different molecular weights
C
same viscosity
D
same vapour density
Official Correct Answer:Option (B)
Step-by-Step Solution:
If two compounds have the same empirical formula but different molecular formulae, they must have different molecular weights. The empirical formula represents the simplest whole-number ratio of the elements in the compound, but it doesn't provide information about the actual number of atoms in a molecule (molecular formula). Because the molecular formula is a multiple of the empirical formula, compounds with different molecular formulae will have different molecular weights even if their empirical formula is the same.
To illustrate with an example, consider the empirical formula CH2. This empirical formula can correspond to several different molecular formulae such as C2H4, C3H6, C4H8, and so on. Each of these molecular formulae has a different molecular weight, even though they share the same empirical formula.
Therefore, the correct option is:
Option B: different molecular weights
Q 77ChemistrySection A • MCQstates of matter
+3 / -1
The volume-temperature graphs of a given mass of an ideal gas at constant pressures are shown below. What is the correct order of pressures?
A
p1>p3>p2
B
p1>p2>p3
C
p2>p3>p1
D
p2>p1>p3
Official Correct Answer:Option (A)
Step-by-Step Solution:
The correct order of pressure is p1>p3>p2.
Q 78ChemistrySection A • MCQpolymers
+3 / -1
Which of the following is cross-linked polymer?
A
Teflon
B
Polythene
C
Nylon
D
Bakelite
Official Correct Answer:Option (D)
Step-by-Step Solution:
A cross-linked polymer is a type of polymer where the individual polymer chains are linked together by covalent bonds, forming a three-dimensional network. This cross-linking process significantly affects the properties of the polymer, making it more rigid, durable, and resistant to heat and chemicals.
Let's evaluate the given options:
Option A: Teflon
Teflon is a brand name for a polymer called polytetrafluoroethylene (PTFE). It is not a cross-linked polymer; rather, it consists of linear chains without cross-linking.
Option B: Polythene
Polythene or polyethylene is a polymer made from ethylene monomers. It can be either low-density polyethylene (LDPE), which has some branching, or high-density polyethylene (HDPE), which is mostly linear. Neither form is typically cross-linked.
Option C: Nylon
Nylon is a type of synthetic polymer, specifically a polyamide. Nylon polymers are generally linear and not cross-linked.
Option D: Bakelite
Bakelite is a type of phenol-formaldehyde resin, which is a thermosetting polymer. Thermosetting polymers are known for their heavily cross-linked structures. Bakelite forms an extensive, three-dimensional network through cross-linking, which makes it very hard and heat-resistant.
Therefore, the correct answer is:
Option D: Bakelite
Q 79ChemistrySection A • MCQchemical bonding and molecular structure
+3 / -1
Which one of the following is/are linear structure?
I. I3−
II. NO2−
III. I3+
IV. SO2
V. N3−
A
I, II and III
B
I and V
C
II, III and IV
D
All of these
Official Correct Answer:Option (B)
Step-by-Step Solution:
I3− ion is made up of an I2 molecule with an I− bonded to it by means of a coordinate bond in which I2 is lone pair acceptor (Lewis acid) and I− is lone pair donor (Lewis base).
There are two bond pairs and three lone pairs in the outer shell of central atom. To minimise the repulsive forces the three lone pairs occupy the equatorial position.
The ion is therefore, linear in shape with a bond angle of exactly 180∘.
Lewis acid I2+ Lewis base I−⟶[I−I←I]−
Similarly, N3− ion is also linear in shape. I3+ does not have linear structure.
Q 80ChemistrySection A • MCQhydrocarbons
+3 / -1
Anti-Markownikoff's addition of HBr is observed in
A
propene
B
but-2-ene
C
pent-2-ene
D
All of these
Official Correct Answer:Option (A)
Step-by-Step Solution:
According to anti-Markownikoffs rule, in the presence of peroxide, addition of HBr takes place to unsymmeterical double bond in such a way that Br− ions adds with carbon having more number of H-atoms.
CH3−CH=CH2+HBrROORCH3−CH2−CH2Br
Q 81ChemistrySection A • MCQhydrogen
+3 / -1
Which of the following is added to remove permanent hardness of water?
A
Cl2
B
Na2CO3
C
Ca(OCl)Cl
D
K2CO3
Official Correct Answer:Option (B)
Step-by-Step Solution:
Permanent hardness of water is caused by the presence of soluble salts of calcium and magnesium, such as calcium chloride (CaCl2) and magnesium sulfate (MgSO4). These salts cannot be removed by simple boiling. One effective method to remove permanent hardness is to convert these soluble salts into insoluble compounds. This can be achieved by adding certain chemicals to the water that react with the calcium and magnesium ions to form precipitates.
Sodium carbonate (Na2CO3), also known as washing soda, is commonly added for this purpose. When sodium carbonate is added to hard water, it reacts with the calcium and magnesium ions to form insoluble carbonates, which can then be removed by filtration. The reactions are as follows:
Ca2++Na2CO3→CaCO3↓+2Na+
Mg2++Na2CO3→MgCO3↓+2Na+
In these reactions, calcium and magnesium ions combine with carbonate ions from sodium carbonate to form insoluble calcium carbonate (CaCO3) and magnesium carbonate (MgCO3) precipitates, respectively.
Therefore, the correct answer is:
Option B
Na2CO3
Q 82ChemistrySection A • MCQp block elements
+3 / -1
Sulphur does not exist as S2 molecule because
A
it is not able to constitute pπ−pπ bonds
B
it is less electronegative
C
it has ability to exhibit catenation
D
of tendency to show variable oxidation states
Official Correct Answer:Option (A)
Step-by-Step Solution:
Sulphur does not exist as S2 molecule primarily because of its inability to constitute pπ−pπ bonds.
In the case of oxygen, the small size of O atoms and the high electronegativity allow the 2p orbitals to overlap effectively, forming a strong pπ−pπ double bond in O2. As a result, molecular oxygen exists as a diatomic molecule. However, sulphur atoms are larger and less electronegative compared to oxygen. This significant size difference makes the overlap between 3p orbitals (the corresponding orbitals in sulphur) less effective for forming strong pπ−pπ double bonds.
Instead, sulphur stabilizes itself more effectively by catenating to form larger molecular structures like S8, where each sulphur atom forms single bonds with adjacent sulphur atoms, creating a puckered ring structure. This results in the elemental sulphur commonly found in the form of octa-atomic rings.
So, the correct answer is:
Option A: it is not able to constitute pπ−pπ bonds
Q 83ChemistrySection A • MCQionic equilibrium
+3 / -1
The concentration of hydrogen ion in a sample of soft drink is 3.8×10−3M. What is its pH ?
A
3.84
B
2.42
C
4.44
D
1.42
Official Correct Answer:Option (B)
Step-by-Step Solution:
The pH of a solution is calculated using the hydrogen ion concentration [H+] with the following formula:
pH=−log[H+]
Given the hydrogen ion concentration in the sample of soft drink is 3.8×10−3M.
To find the pH, we substitute the given [H+] value into the formula:
pH=−log(3.8×10−3)
Breaking it down, we have:
pH=−(log(3.8)+log(10−3))
Recall that log(10−3)=−3, thus:
pH=−(log(3.8)−3)
pH=−log(3.8)+3
Now, finding the logarithm value of 3.8 using a calculator:
log(3.8)≈0.58
Hence:
pH=−0.58+3
pH≈2.42
Thus, the pH of the soft drink is approximately 2.42.
Therefore, the correct option is: Option B (2.42)
Q 84ChemistrySection A • MCQhydrocarbons
+3 / -1
Identify product (Z) in the series, of reaction
CH2=CH2HBrXaq.KOHYNa2CO3I2 excess Z
A
C2H5I
B
C2H5OH
C
CHI3
D
CH3CHO
Official Correct Answer:Option (C)
Step-by-Step Solution:
Let's go through the sequence of reactions step by step to identify the final product (Z).
Step 1: CH2=CH2HBrX
The addition of hydrogen bromide (HBr) to ethene (CH2=CH2) follows Markovnikov's rule, forming bromoethane (C2H5Br) as the product.
CH2=CH2+HBr→C2H5Br
So, X is C2H5Br.
Step 2: C2H5Braq.KOHY
When bromoethane reacts with aqueous potassium hydroxide (KOH), nucleophilic substitution occurs, converting bromoethane to ethanol (C2H5OH).
C2H5Br+KOH→C2H5OH+KBr
So, Y is C2H5OH.
Step 3: C2H5OHNa2CO3I2 excess Z
Ethanol (ethyl alcohol) reacts with iodine (I2) in the presence of sodium carbonate (Na2CO3) to form iodoform (CHI3). This reaction is known as the iodoform test, which is a common qualitative test for the presence of methyl ketones and ethanol.
C2H5OH+4I2+Na2CO3→CHI3+5NaI+HCOONa+2H2O
So, Z is CHI3 (iodoform).
Therefore, the correct answer is:
Option C: CHI3
Q 85ChemistrySection A • MCQsolid state
+3 / -1
A compound formed by elements A and B crystallises in the cubic structure where A atoms are at the corners of a cube and B atoms are at the face centre. The formula of the compound is :
A
AB3
B
A2B
C
AB2
D
A2B3
Official Correct Answer:Option (A)
Step-by-Step Solution:
To determine the formula of the compound, we need to calculate the number of atoms of each type (A and B) in the unit cell of the crystal structure.
Firstly, let’s consider the A atoms which are located at the corners of the cube. In a cubic structure, each corner atom is shared among 8 adjacent unit cells. Thus, each corner contributes only 81 of an atom to a single unit cell. Since there are 8 corners in a cube:
Number of A atoms=8×81=1
Next, consider the B atoms which are located at the face centers of the cube. Each face-centered atom is shared between 2 adjacent unit cells, therefore each face-centered atom contributes 21 of an atom to a single unit cell. Since there are 6 faces in a cube:
Number of B atoms=6×21=3
Thus, in one unit cell, there is 1 A atom and 3 B atoms. Therefore, the formula of the compound is:
AB3
So the correct answer is:
Option A: AB3
Q 86ChemistrySection A • MCQatomic structure
+3 / -1
Which of the following statements does not form a part of Bohr's model of hydrogen atom?
A
The position and velocity of the electrons in the orbit cannot be determined simultaneously.
B
The electron in the orbit nearest the nucleus has the lowest energy.
C
Electrons revolve in different orbits around the nucleus.
D
Energy of the electrons in the orbit is quantised.
Official Correct Answer:Option (A)
Step-by-Step Solution:
Bohr's model of the hydrogen atom primarily describes the behavior of electrons in fixed orbits around the nucleus with quantized energy levels. Below is an analysis of each statement:
Option A: The position and velocity of the electrons in the orbit cannot be determined simultaneously.
This statement refers to the Heisenberg Uncertainty Principle and is not a part of Bohr's model. The Bohr model assumes electrons have well-defined orbits with known velocities and positions.
Option B: The electron in the orbit nearest the nucleus has the lowest energy.
This is indeed a part of Bohr's model. Bohr postulated that electrons occupy specific energy levels, and the closest orbit to the nucleus has the least energy.
Option C: Electrons revolve in different orbits around the nucleus.
This statement is a fundamental aspect of Bohr's model, where electrons move in discrete orbits or energy levels around the nucleus.
Option D: Energy of the electrons in the orbit is quantised.
This statement is also a key component of Bohr's model. Bohr proposed that the energy of electrons in these orbits is quantized, meaning electrons can only occupy certain energy levels.
Given the analysis, the statement that does not form a part of Bohr's model of hydrogen atom is:
Option A: The position and velocity of the electrons in the orbit cannot be determined simultaneously.
Q 87ChemistrySection A • MCQcoordination compounds
+3 / -1
The complex showing a spin-only magnetic moment of 2.82BM is
A
[Ni(Cl)4]3−
B
[NiCl4]2−
C
Ni(PPh3)4
D
[Ni(CN)4]2−
Official Correct Answer:Option (B)
Step-by-Step Solution:
Ni:3d8,4s2Ni2+:3d8
Since, Cl is a weak field ligand, it doesn't cause pairing of electron.
Number of unpaired electrons, n=2
μ=n(n+2)=2(2+2)BM=8BM=2.82BM
Q 88ChemistrySection A • MCQp block elements
+3 / -1
Which of the following oxides is amphoteric in character?
A
SnO2
B
SiO2
C
CO2
D
CaO
Official Correct Answer:Option (A)
Step-by-Step Solution:
The term "amphoteric" refers to a substance that can react both as an acid and as a base. In the context of oxides, an amphoteric oxide can react with both acids and bases to form salts and water. Let's analyze the options presented:
Option A: SnO2 (Tin(IV) oxide) This oxide is known to be amphoteric. It can react with acids to form stannic salts and with strong bases to form stannates.
Option B: SiO2 (Silicon dioxide) This oxide is acidic in nature. It primarily reacts with bases (such as sodium hydroxide) but not with acids.
Option C: CO2 (Carbon dioxide)
Option D: CaO (Calcium oxide) This oxide is basic. It reacts with acids to form calcium salts and water but not with bases.
Among the given options, the correct answer is Option A: SnO2, which is amphoteric in character.
Q 89ChemistrySection A • MCQbiomolecules
+3 / -1
Glucose and mannose are related as
A
epimers
B
anomers
C
ketohexoses
D
disaccharides
Official Correct Answer:Option (A)
Step-by-Step Solution:
Carbohydrates which differ in configuration at a carbon other than the anomeric carbon. Glucose and mannose are differ in configuration around C2 and hence these are C2 epimers.
Q 90ChemistrySection A • MCQchemical bonding and molecular structure
+3 / -1
In BrF3 molecule, the lone pairs occupy equatorial positions to minimise
A
lone pair-bond pair repulsion only
B
bond pair-bond pair repulsion only
C
lone pair-lone pair repulsion and lone pair-bond pair repulsion
D
lone pair-lone pair repulsion only
Official Correct Answer:Option (C)
Step-by-Step Solution:
In BrF3 molecule, Br is sp3d hybridised, but geometry is T-shaped due to distortion of geometry from trigonal-bipyramidal to T-shaped by the involvement of lone pair-lone pair repulsion. The lone pair occupies equitorial position in order to minimize lone pair-lone pair and lone pair-bond pair repulsion.
Q 91ChemistrySection A • MCQgeneral organic chemistry
+3 / -1
In electrophilic aromatic substitution reaction, the nitro group is meta-directing because it
A
decreases electron density at ortho-and para-positions
B
decreases electron density at meta-position
C
increases electron density at meta-position
D
increases electron density at ortho-and para-positions
Official Correct Answer:Option (A)
Step-by-Step Solution:
In electrophilic aromatic substitution (EAS) reactions, the nitro group (NO2) is known to be a strong electron-withdrawing group due to its resonance and inductive effects. This property significantly influences the electron distribution in the aromatic ring, thereby affecting the position where incoming electrophiles are most likely to attack.
Let's analyze the options provided in this context:
Option A: Decreases electron density at ortho-and para-positions
Option B: Decreases electron density at meta-position
Option C: Increases electron density at meta-position
Option D: Increases electron density at ortho-and para-positions
The nitro group, being electron-withdrawing, pulls electron density away from the aromatic ring through two main mechanisms:
Inductive Effect: The nitro group withdraws electron density through the sigma bonds due to its high electronegativity.
Resonance Effect: The nitro group can participate in resonance, pulling electron density away from the ring, particularly affecting the ortho and para positions relative to the nitro group.
Due to the electron-withdrawing nature of the nitro group, electron density is significantly reduced at the ortho and para positions more than the meta positions. This makes the ortho and para positions less reactive towards electrophiles since electrophiles are attracted to electron-rich areas.
As a result, the meta position remains relatively electron-rich in comparison to the ortho and para positions. Thus, the electrophilic substitution is more likely to occur at the meta position.
Based on this understanding, the correct answer is:
Option A: Decreases electron density at ortho-and para-positions
Q 92ChemistrySection A • MCQhydrogen
+3 / -1
Which of the following acts as interstitial hydride?
A
NH3
B
CH4
C
ZnH2
D
H2O
Official Correct Answer:Option (C)
Step-by-Step Solution:
The correct answer is Option C: ZnH2. Here's why:
Interstitial hydrides are metallic hydrides formed when hydrogen atoms occupy the interstitial spaces (voids) within the crystal lattice of a transition metal. These hydrides are typically non-stoichiometric, meaning the ratio of metal to hydrogen atoms is not fixed and can vary depending on the conditions.
Let's analyze the options:
A) NH3 (Ammonia): Ammonia is a covalent compound with a strong N-H bond. It does not form an interstitial hydride.
B) CH4 (Methane): Methane is a covalent compound with strong C-H bonds. It does not form an interstitial hydride.
C) ZnH2 (Zinc Hydride): Zinc is a transition metal, and its hydride, ZnH2, is a classic example of an interstitial hydride. Hydrogen atoms occupy the interstitial sites within the zinc crystal lattice.
D) H2O (Water): Water is a covalent compound with strong O-H bonds. It does not form an interstitial hydride.
Therefore, only ZnH2 fits the definition of an interstitial hydride.
Q 93ChemistrySection A • MCQthermodynamics
+3 / -1
A mixture of two moles of carbon monoxide and one mole of oxygen, in a closed vessel is ignited to convert the carbon monoxide to carbon dioxide. If ΔH is the enthalpy change and ΔE is the change in internal energy, then
A
ΔH>ΔU
B
ΔH<ΔU
C
ΔH=ΔU
D
the relationship depends on the capacity of the vessel
Official Correct Answer:Option (B)
Step-by-Step Solution:
To determine the relationship between the enthalpy change (ΔH) and the internal energy change (ΔE) for the given reaction, we need to examine the process and consider the relevant thermodynamic equations.
The reaction given is the combustion of carbon monoxide:
2CO+O2→2CO2
We know that this reaction occurs in a closed vessel, which implies a constant volume process. The relationship between enthalpy change and internal energy change for a reaction can be described by the equation:
ΔH=ΔE+ΔngRT
Where:
ΔH is the enthalpy change
ΔE is the internal energy change
Δng is the change in the number of moles of gases
R is the universal gas constant
T is the temperature in Kelvin
To determine Δng, we need to look at the number of moles of gas before and after the reaction:
Before the reaction: 2 moles of CO and 1 mole of O2, totaling 3 moles of gas.
After the reaction: 2 moles of CO2.
Hence, Δng can be calculated as:
Δng=nfinal−ninitial=2−3=−1
Substituting Δng=−1 into the enthalpy-internal energy relationship:
ΔH=ΔE+(−1)RT
ΔH=ΔE−RT
Since RT is always a positive quantity, it means that:
ΔH<ΔE
Therefore, the correct answer is:
Option B: ΔH<ΔU
Q 94ChemistrySection A • MCQs block elements
+3 / -1
Which one of the following decreasing orders of stability is correct?
A
MgCO3>CaCO3>SrCO3>BaCO3
B
BaCO3>SrCO3>CaCO3>MgCO3
C
MgCO3>BaCO3>SrCO3>CaCO3
D
CaCO3>BaCO3>MgCO3>SrCO3
Official Correct Answer:Option (B)
Step-by-Step Solution:
The correct order of decreasing stability of carbonates is:
BaCO3>SrCO3>CaCO3>MgCO3
Therefore, the answer is Option B.
Let's understand why this is the case. The stability of carbonates is related to the size of the metal cation. As we move down the group in the periodic table, the size of the metal cation increases. A larger cation has a weaker attraction to the carbonate anion. This weaker attraction makes the carbonate less stable.
Here's a breakdown:
Ba2+ is the largest cation and therefore has the weakest attraction to the carbonate anion, making BaCO3 the most stable.
Sr2+ is smaller than Ba2+, leading to a stronger attraction and less stability compared to BaCO3.
Ca2+ is smaller than Sr2+, making CaCO3 less stable than SrCO3.
Mg2+ is the smallest cation, resulting in the strongest attraction and the least stable carbonate, MgCO3.
Q 95ChemistrySection A • MCQthermodynamics
+3 / -1
The temperature of K at which ΔG=0, for a given reaction with ΔH=−20.5kJmol−1 and ΔS=−50.0JK−1mol−1 is
A
−410
B
410
C
2.44
D
−2.44
Official Correct Answer:Option (B)
Step-by-Step Solution:
To determine the temperature K at which ΔG=0 for a given reaction, we use the relationship between the Gibbs free energy change (ΔG), enthalpy change (ΔH), and entropy change (ΔS), expressed by the Gibbs free energy equation:
ΔG=ΔH−TΔS
Given that ΔG=0, we set the equation as follows:
0=ΔH−TΔS
Solving for the temperature T, we get:
T=ΔSΔH
Now, we can plug in the given values:
ΔH=−20.5kJmol−1=−20500Jmol−1
ΔS=−50.0JK−1mol−1
Substituting these values into the equation:
T=−50.0JK−1mol−1−20500Jmol−1
T=50.020500
T=410K
Therefore, the temperature K at which ΔG=0 is 410 K. The correct answer is:
Option B
410
Q 96ChemistrySection A • MCQhydrocarbons
+3 / -1
In acetylene molecule between the carbon atoms there are
A
three π-bonds
B
one σ-and two π-bonds
C
two σ-and no π-bonds
D
three σ-bonds
Official Correct Answer:Option (B)
Step-by-Step Solution:
The structure of acetylene is
In acetylene, both the C-atoms are sp-hybridised. Hence, in acetylene molecule, there are one sigma and two pi bonds are present between carbon atoms.
Q 97ChemistrySection A • MCQgeneral organic chemistry
+3 / -1
The decreasing order of nucleophilicity among the following nucleophiles is
A
III, II, I, IV
B
II, III, I, IV
C
IV, III, II, I
D
I, II, III, IV
Official Correct Answer:Option (B)
Step-by-Step Solution:
If acid is weak, its conjugate base (nucleophile) is strong and vice-versa.
I. is conjugate base of
II. CH3O− is a conjugate base of CH3OH
III. CN− is a conjugate base of HCN
IV. is a conjugate base of
Order of acidic nature is IV > I > III > II.
So, nucleophilicity order is II > III > I > IV.
Q 98ChemistrySection A • MCQcoordination compounds
+3 / -1
The correct statement with respect to the complexes Ni(CO)4 and [Ni(CN)4]2− is
A
nickel is in the same oxidation state in both.
B
Both have square planar geometry.
C
have square planar and tetrahedral geometry, respectively.
D
have tetrahedral and square planar geometry, respectively.
Official Correct Answer:Option (D)
Step-by-Step Solution:
To determine the correct statement with respect to the complexes Ni(CO)4 and [Ni(CN)4]2−, we need to analyze their coordination, oxidation states, and molecular geometries.
Option A: Nickel is in the same oxidation state in both.
To find the oxidation state of Ni in Ni(CO)4, we consider that CO is a neutral ligand. Therefore, the oxidation state of Ni here is +0.
In [Ni(CN)4]2−, since CN is a -1 ligand and the overall charge on the complex is -2, the oxidation state of Ni is +2.
So, nickel is not in the same oxidation state in both complexes.
Option B: Both have square planar geometry.
To determine the geometry, we need to consider the electronic configuration and the nature of the ligands:
Ni(CO)4: This complex has Ni in the 0 oxidation state with an electronic configuration of 3d84s2. CO is a strong field ligand but with a d10 configuration (Ni(0)), leading to a tetrahedral geometry.
[Ni(CN)4]2−: This complex has Ni in the +2 oxidation state with an electronic configuration of 3d8. CN is a strong field ligand, causing a square planar geometry due to the dsp² hybridization to minimize repulsion.
Thus, both do not have square planar geometry.
Option C: Have square planar and tetrahedral geometry, respectively.
Based on our analysis of the electronic configuration and hybridization, it is clear that Ni(CO)4 has a tetrahedral geometry and [Ni(CN)4]2− has a square planar geometry.
Hence, this statement is incorrect because it is the opposite of our findings.
Option D: Have tetrahedral and square planar geometry, respectively.
From the above analysis:
Ni(CO)4: Tetrahedral geometry.
[Ni(CN)4]2−: Square planar geometry.
This statement is correct based on our conclusions.
Therefore, the correct answer is Option D: Have tetrahedral and square planar geometry, respectively.
Q 99ChemistrySection A • MCQbiomolecules
+3 / -1
A certain compound gives negative test with ninhydrin and positive test with Benedict's solution, it is
A
an amino acid
B
a monosaccharide
C
a lipid
D
a protein
Official Correct Answer:Option (B)
Step-by-Step Solution:
To determine which compound is being described, we need to analyze the given chemical tests and their results:
1. Negative test with ninhydrin: Ninhydrin is a chemical reagent commonly used to detect amino acids and proteins. When it reacts with these compounds, it typically produces a deep purple color known as Ruhemann's purple. Therefore, a negative test with ninhydrin implies that the compound does not contain free amino groups, ruling out amino acids (Option A) and proteins (Option D).
2. Positive test with Benedict's solution: Benedict's solution is used to test for the presence of reducing sugars. If the compound is a reducing sugar, it will reduce the copper(II) ions in Benedict's solution to form a brick-red precipitate of copper(I) oxide when heated. Therefore, a positive test with Benedict's solution indicates the presence of a reducing sugar.
Given these observations, the compound must be a reducing sugar. Thus, the correct answer is:
Option B: a monosaccharide.
Q 100ChemistrySection A • MCQchemistry in everyday life
+3 / -1
Match the following columns.
Column I
Column II
(A)
Sodium perborate
1
Disinfectant
(B)
Chlorine
(Q)
Antiseptic
(C)
Bithional
(R)
Milk bleaching agent
(D)
Potassium stearate
(S)
Soap
Choose the correct options.
A
A - 1, B - 2, C - 3, D - 4
B
A - 2, B - 3, C - 4, D - 1
C
A - 3, B - 1, C - 2, D - 4
D
A - 4, B - 1, C - 2, D - 3
Official Correct Answer:Option (C)
Step-by-Step Solution:
Here's a breakdown of the matching and why the correct answer is Option C:
Let's analyze each compound and its corresponding use:
(A) Sodium perborate is a common ingredient in laundry detergents and is known for its bleaching and stain-removing properties. Therefore, it's linked to (R) Milk bleaching agent.
(B) Chlorine is a powerful disinfectant and is widely used in water treatment, sanitation, and cleaning. It's a strong disinfectant, so it matches (1) Disinfectant.
(C) Bithional is an antiseptic agent commonly found in soaps and personal care products. It helps prevent the growth of bacteria and fungi. Therefore, it matches (2) Antiseptic.
(D) Potassium stearate is a major component of soap. It acts as a surfactant, helping to remove dirt and grease through emulsification. This matches (4) Soap.
Therefore, the correct matching is:
A - 3, B - 1, C - 2, D - 4
This corresponds to Option C.
Q 101PhysicsSection A • MCQelectromagnetic waves
+3 / -1
The electric and the magnetic field associated with an E.M. wave, propagating along the Z-axis can be represented by
A
(E=E0i^,B=B0j^)
B
(E=E0k^,B=B0i^)
C
(E=E0j^,B=B0i^)
D
(E=E0j^,B=B0k^)
Official Correct Answer:Option (A)
Step-by-Step Solution:
The direction of propagation of EM waves is always perpendicular to both the electric and magnetic fields. Therefore, +vex and +vey directions should be the directions of the electric and magnetic fields, respectively.
Q 102PhysicsSection A • MCQwork power and energy
+3 / -1
The potential energy for a force field F is given by u(x,y)=cos(x+y). The force acting on a particle at position given by co-ordinates (0,π/6) is
A
2−1(i^+j^)
B
21(i^+j^)
C
21i^+23j^
D
21i^−23j^
Official Correct Answer:Option (B)
Step-by-Step Solution:
To find the force acting on a particle in a force field given by a potential energy function, we can use the relationship between force and potential energy. The force is the negative gradient of the potential energy function:
F=−∇u(x,y)
Given the potential energy function:
u(x,y)=cos(x+y)
The gradient operator ∇ in two dimensions is given by:
∇=(∂x∂,∂y∂)
To find the force, we first need to compute the partial derivatives of u(x,y) with respect to x and y.
Calculate the partial derivative of u(x,y) with respect to x:
∂x∂u=∂x∂cos(x+y)=−sin(x+y)
Now, calculate the partial derivative of u(x,y) with respect to y:
∂y∂u=∂y∂cos(x+y)=−sin(x+y)
So the gradient of u(x,y) is:
∇u(x,y)=(−sin(x+y),−sin(x+y))
The force F is the negative of this gradient:
F=−∇u(x,y)=(sin(x+y),sin(x+y))
We need to evaluate this at the coordinates (0,π/6):
(x,y)=(0,π/6)
Substitute these values into the sine function:
sin(0+π/6)=sin(π/6)=21
Thus, the force F at (0,π/6) is:
F=(21,21)
In vector notation, this can be written as:
F=21i^+21j^
This matches with Option B:
21(i^+j^)
Q 103PhysicsSection A • MCQalternating current
+3 / -1
A direct current of 10A is superimposed on an alternating current i=10sinωt flowing through the wire. The effective value of the resulting current will be.
A
(15/2)A
B
56A
C
55A
D
15A
Official Correct Answer:Option (B)
Step-by-Step Solution:
The resulting current is the sum of the direct current and the alternating current:
I=Idc+Iac=10+10sinωt
To find the effective value (also known as the root-mean-square or RMS value), we need to calculate the square root of the mean of the squared current:
Irms=T1∫0TI2dt
where T is the period of the alternating current.
Let's substitute the expression for I and simplify:
Irms=T1∫0T(10+10sinωt)2dt
Expanding the square and integrating term by term:
Irms=T1∫0T(100+200sinωt+100sin2ωt)dt
We know that the average value of sinωt over a complete cycle is zero, and the average value of sin2ωt over a complete cycle is 21. Therefore:
Irms=T1(100T+0+100⋅21T)=150
Simplifying further:
Irms=56A
Therefore, the correct answer is Option B: 56A.
Q 104PhysicsSection A • MCQdual nature of radiation
+3 / -1
When 0.25Ao X-Rays strike a material, the photoelectrons from the K shell are observed to more in a circle of radius 23mm in magnetic field of 4×10−2 tesla active perpendicularly to the direction of emission of photoelectrons. What is the Binding energy of K shell electrons?
A man of mass m starts falling towards a planet of mass M and radius R. As he reaches near to the surface, he realizes that will pass through a small role in the planet. As he enters the role, we sees that the planet is really made of two pieces a spherical shell of negligible thickness of mass 3M/4 and a point mass M/4 at the centre. Change in the force of gravity experienced by the man is
A
43R2GMm
B
0
C
31R2GMm
D
34R2GMm
Official Correct Answer:Option (A)
Step-by-Step Solution:
When the man is outside the planet and close to its surface, the gravitational force is determined by the entire mass of the planet, M. The force of gravity at the surface can be given by Newton's law of gravitation:
F=R2GMm
However, as the man passes through the hole in the planet, the gravitational force he experiences changes due to the unique mass distribution of the planet. The planet consists of a spherical shell of mass 43M and negligible thickness, and a point mass 4M at the center.
Let's analyze the gravitational force when the man is inside the planet:
1. Spherical Shell Contribution:
A spherical shell of uniform density exerts no net gravitational force on a particle located inside it. Thus, the man inside the shell experiences no force from the spherical shell of mass 43M.
2. Point Mass Contribution:
The point mass at the center, which is 4M, exerts a gravitational force on the man. According to Newton's law of gravitation, this force is given by:
F′=R2G(4M)m
To determine the change in the force of gravity experienced by the man, we subtract the force due to the point mass from the original force at the planet's surface:
Original force at the surface:
F=R2GMm
Force inside due to point mass:
F′=41R2GMm
Change in the force:
ΔF=F−F′
ΔF=R2GMm−41R2GMm
Simplifying the expression:
ΔF=R2GMm(1−41)
ΔF=R2GMm⋅43
ΔF=43R2GMm
Hence, the change in the force of gravity experienced by the man is
43R2GMm
The correct answer is Option A: 43R2GMm.
Q 106PhysicsSection A • MCQdual nature of radiation
+3 / -1
An electron of mass m and charge e initially at rest gets accelerated by a constant field 2E. The rate of change of de-Broglie wavelength of this electron at time t ignoring relativistic effects is
A
−(2eEt2)h
B
2E−eht
C
(eEt2−2mh)
D
(eE−h)
Official Correct Answer:Option (A)
Step-by-Step Solution:
To determine the rate of change of the de-Broglie wavelength of the electron at time t, we need to start with the expression for the de-Broglie wavelength, which is given by
λ=ph
where h is Planck's constant and p is the momentum of the electron.
Since the electron experiences a constant electric field of 2E, it undergoes a uniform acceleration. The force F on the electron is given by
F=e⋅2E=2eE
This force causes the electron to accelerate, so the acceleration a is given by
a=mF=m2eE
Initially, the electron is at rest, so its velocity v at time t can be obtained using the equation of motion:
v=u+at=0+(m2eE)t=m2eEt
The momentum p of the electron at time t is given by
p=mv=m(m2eEt)=2eEt
Now substituting the expression for momentum into the de-Broglie wavelength equation, we get
λ=ph=2eEth
To find the rate of change of de-Broglie wavelength with respect to time, we take the derivative of λ with respect to t:
Thus, the rate of change of de-Broglie wavelength of the electron at time t is
dtdλ=2eEt2−h
So the correct answer is:
Option A: −(2eEt2)h
Q 107PhysicsSection A • MCQatoms and nuclei
+3 / -1
After two hours one-eight of the starting amount of a certain radioactive isotope remained undecayed. The half-life of the isotope is
A
15 min
B
40 min
C
45 min
D
4 h
Official Correct Answer:Option (B)
Step-by-Step Solution:
To determine the half-life of the radioactive isotope, we need to use the information given and the formula for radioactive decay. The formula for radioactive decay is:
N(t)=N0(21)T21t
where:
N(t) is the remaining quantity of the isotope at time t.
N0 is the initial quantity of the isotope.
T21 is the half-life of the isotope.
t is the elapsed time.
According to the given information, after 2 hours (which is 120 minutes), one-eighth of the starting amount of the isotope remains undecayed. Therefore, if N0N(t)=81, we can write:
N0N(t)=(21)T21t
Substituting the values we have:
81=(21)T21120
We know that 81 can be written as (21)3, therefore:
(21)3=(21)T21120
By equating the exponents, we get:
3=T21120
Solving for T21:
T21=3120=40minutes
Thus, the half-life of the isotope is 40 minutes. Therefore, the correct option is:
Option B: 40 min
Q 108PhysicsSection A • MCQelasticity
+3 / -1
For a constant hydraulic stress on an object, the fractional change in the object's volume (ΔV/V) and its bulk modulus B are related as
A
VΔV∝B
B
VΔV∝B2
C
VΔV∝B1
D
VΔV∝B21
Official Correct Answer:Option (C)
Step-by-Step Solution:
To understand the relationship between the fractional change in volume of an object (ΔV/V) and its bulk modulus (B) under a constant hydraulic stress, we need to recall the definition and formula of bulk modulus.
The bulk modulus (B) is defined as the ratio of the hydraulic stress (pressure change) to the corresponding relative change in volume (fractional change in volume). Mathematically, it can be expressed as:
B=−VΔVΔP
where:
B is the bulk modulus
(ΔP) is the change in pressure (hydraulic stress)
(ΔV/V) is the fractional change in volume
From the above equation, we can solve for the fractional change in volume (ΔV/V):
VΔV=−BΔP
Here, it becomes clear that the fractional change in volume (ΔV/V) is inversely proportional to the bulk modulus (B), assuming the change in pressure (ΔP) remains constant. This means that if the bulk modulus increases, the fractional change in volume decreases, and vice versa.
Thus, the correct option is:
Option C
VΔV∝B1
Q 109PhysicsSection A • MCQsemiconductor devices and logic gates
+3 / -1
Truth table for system of four NAND gate and one NOT gate as shown in figure is.
Two rings of radius R and nR made of same material have the ratio of moment of inertia about an axis passing through centre is 1:64. The value of n is
A
2
B
22
C
4
D
1/2
Official Correct Answer:Option (C)
Step-by-Step Solution:
To determine the value of n, let's analyze the problem by considering the moment of inertia for each ring about an axis passing through its center. For a ring, the moment of inertia about an axis through its center can be expressed as:
I=mR2
Where:
I is the moment of inertia
m is the mass of the ring
R is the radius of the ring
Given that both rings are made of the same material, they will have the same density. Let's denote the moment of inertia of the first ring (radius R) as I1 and the moment of inertia of the second ring (radius nR) as I2. According to the problem:
I2I1=641
For the first ring (radius R):
I1=m1R2
For the second ring (radius nR):
I2=m2(nR)2=m2n2R2
Assuming both rings are made of the same material and have the same mass per unit length, the mass of the second ring with radius nR will be n times the mass of the first ring (since circumference scales linearly with radius):
m2=nm1
Then we can write:
I2=nm1(nR)2=nm1n2R2=n3m1R2
Using the ratio of the moments of inertia:
I2I1=n3m1R2m1R2=n31=641
The above equality simplifies to:
n3=64
n=364=4
Thus, the value of n is:
Option C
Q 111PhysicsSection A • MCQheat and thermodynamics
+3 / -1
A Carnot's heat engine works between the temperature 527∘C and 127∘C. What amount of heat should it consume per second to deliver mechanical work at the rate of 1.0kW ?
A
0.477 kcal/s
B
4.77 kcal/s
C
447.7 kcal/s
D
0.2385 kcal/s
Official Correct Answer:Option (A)
Step-by-Step Solution:
A Carnot heat engine operates between two temperatures: the hot reservoir temperature (Th) and the cold reservoir temperature (Tc). To find the efficiency (η) of a Carnot engine, we use the formula:
η=1−ThTc
where both temperatures (Th and Tc) must be in absolute temperature, i.e., Kelvin (K).
The given temperatures are 527∘C and 127∘C. First, we convert these temperatures to Kelvin:
Th=527∘C+273=800K
Tc=127∘C+273=400K
Next, we calculate the efficiency of the Carnot engine:
η=1−800400=1−0.5=0.5
The efficiency (η) is equal to the fraction of heat converted to work. Therefore, the fraction of heat used to do mechanical work per second is:
η=QhW
where W is the work done per second (which is 1.0kW or 1000W), and Qh is the heat consumed per second.
Rearranging the formula, we get:
Qh=ηW
Substituting the given values:
Qh=0.51000W=2000W
To convert the heat consumed per second from Watts to kcal/s, we use the conversion factor 1kcal/s=4184W:
Qh=4184W/kcal2000W≈0.477kcal/s
Therefore, the amount of heat the Carnot engine should consume per second to deliver mechanical work at the rate of 1.0kW is:
Option A: 0.477 kcal/s
Q 112PhysicsSection A • MCQatoms and nuclei
+3 / -1
The total energy of an electron in the second excited state of hydrogen atom is about −1.51eV. Its kinetic energy in this state is
A
−1.5eV
B
−3.02eV
C
3.02 eV
D
1.51 eV
Official Correct Answer:Option (D)
Step-by-Step Solution:
Potential energy of an electron
(U)=−2 (kinetic Energy K)
So, total energy, E=U+K=−2K+K
E⇒K=−K=−E⇒K=−(−1.51eV)=1.51eV
Q 113PhysicsSection A • MCQrotational motion
+3 / -1
A thin but rigid semicircular wire frame of radius r is hinged at O and can rotate in its own vertical plane. A smooth peg P starts from O and moves horizontally with constant speed 2v0 lifting the frame upward as shown in figure. Find the angular velocity ω of the frame when its diameter makes an angle of 60∘ with vertical.
Water is flowing on a horizontal fixed surface such that its flow velocity varies with y (vertical direction) as v=k(a22y2−a3y3). If coefficient of viscosity for water is 2η. What will the shear stress between layers of water at y=a ?
A
a2ηk
B
kaη
C
2kηa
D
None of these
Official Correct Answer:Option (A)
Step-by-Step Solution:
To determine the shear stress between layers of water at y=a, we start by using the given velocity profile and the definition of shear stress for a fluid in laminar flow.
The shear stress τ in a fluid is given by:
τ=ηdydu
where η is the dynamic viscosity of the fluid, and dydu is the velocity gradient in the direction perpendicular to the flow.
Given the velocity profile:
v=k(a22y2−a3y3)
First, we need to calculate the velocity gradient dydv:
Now, using the given viscosity of the water, 2η, the shear stress τ is given by:
τ=2η(ak)=a2ηk
Therefore, the shear stress between layers of water at y=a is:
τ=a2ηk
The correct option is Option A:
a2ηk
Q 117PhysicsSection A • MCQdual nature of radiation
+3 / -1
In an electron gun the potential difference between the filament and plate is 4000V. What will be the velocity of electron emitting from the gain?
A
3×103m/s
B
3.18×107m/s
C
3.52×107m/s
D
3.75×107m/s
Official Correct Answer:Option (D)
Step-by-Step Solution:
To determine the velocity of the electron emitted from the gun, we need to apply the concept of energy conservation. Specifically, the kinetic energy (KE) gained by the electron will be equal to the electrostatic potential energy (PE) provided by the potential difference (V) between the filament and the plate.
The electrostatic potential energy can be expressed as:
PE=eV
where:
e is the charge of the electron, approximately 1.6×10−19 C
V is the potential difference, which is given as 4000 V
The kinetic energy of the electron can be expressed as:
KE=21mv2
where:
m is the mass of the electron, approximately 9.1×10−31 kg
v is the velocity of the electron we need to determine.
Equating the kinetic energy to the potential energy, we have:
eV=21mv2
Rearranging the equation to solve for the velocity v gives:
v=m2eV
Substituting the given values:
v=9.1×10−312×1.6×10−19×4000
v=9.1×10−311.28×10−15
v=1.41×1015
v≈3.75×107 m/s
Therefore, the correct option is:
Option D: 3.75×107m/s
Q 118PhysicsSection A • MCQmagnetism and matter
+3 / -1
Magnetic moment of bar magnet is 2M. The work done to turn the magnet by 90∘ of magnet in direction of magnetic field B/2 will be
A
zero
B
2MB
C
2MB
D
MB
Official Correct Answer:Option (D)
Step-by-Step Solution:
To find the work done in turning the magnet, we need to understand the relationship between the magnetic moment, the magnetic field, and the potential energy in the system. The potential energy (U) of a magnetic dipole in a magnetic field is given by the formula:
U=−M⋅B
where:
M = Magnetic moment vector
B = Magnetic field vector
For a bar magnet with a magnetic moment 2M in a magnetic field 2B, the potential energy can be simplified as:
U=−(2M)(2B)cos(θ)
Initially, let's consider when the magnet is aligned with the magnetic field:
θ=0∘
U1=−(2M)(2B)cos(0∘)
U1=−(2M)(2B)⋅1
U1=−MB
Next, let's consider the state when the magnet is turned by 90∘:
θ=90∘
U2=−(2M)(2B)cos(90∘)
U2=−(2M)(2B)⋅0
U2=0
The work done (W) is equal to the change in potential energy, which is:
W=U1−U2
W=(−MB)−0
W=MB
Hence, the work done to turn the magnet by 90∘ in a magnetic field 2B is:
Option D: MB
Q 119PhysicsSection A • MCQsemiconductor devices and logic gates
+3 / -1
A common emitter amplifier has a voltage gain of 50 an input impedance of 100 Ω and an output impedance of 400 Ω. The power gain of the amplifier is
A
500
B
1000
C
625
D
50
Official Correct Answer:Option (C)
Step-by-Step Solution:
To find the power gain of the amplifier, we first need to understand the relationship between voltage gain, input impedance, and output impedance.
The power gain (GP) of an amplifier is given by the product of the voltage gain (GV) and the current gain (GI). However, we can derive it directly from the voltage gain and the impedance values.
Given:
Voltage gain (GV) = 50
Input impedance (Rin) = 100 Ω
Output impedance (Rout) = 400 Ω
We know that:
GP=Vin2/RinVout2/Rout
Since the voltage gain is:
GV=VinVout=50
Substituting GV=50 into the power gain formula:
GP=(VinVout)2⋅RoutRin=GV2⋅RoutRin
So we have:
GP=502⋅400100
GP=2500⋅0.25
GP=625
Hence, the power gain of the amplifier is 625.
Therefore, the correct option is:
Option C - 625
Q 120PhysicsSection A • MCQalternating current
+3 / -1
A resistance R and inductance L and a capacitor C all are connected in series with an AC supply. The resistance of R is 24ohm and for a given frequency, the inductive reactance of L is 36 ohm and capacitive reactance of C is 24ohm. If the current in the circuit is 5amp. Find the potential difference across R,L and C.
A
140,140,120V
B
80,120,120V
C
140,140,120V
D
120,180,120V
Official Correct Answer:Option (D)
Step-by-Step Solution:
To determine the potential differences across the resistor R, inductor L, and capacitor C in a series AC circuit, we can use Ohm's Law and the given impedances.
Given:
R=24 ohm
Inductive reactance XL=36 ohm
Capacitive reactance XC=24 ohm
Current in the circuit I=5 amp
First, we find the potential difference across each component using Ohm's Law:
Potential difference across R:
VR=I⋅R
VR=5 amp⋅24 ohm
VR=120 V
Potential difference across L:
VL=I⋅XL
VL=5 amp⋅36 ohm
VL=180 V
Potential difference across C:
VC=I⋅XC
VC=5 amp⋅24 ohm
VC=120 V
Summarizing, the potential differences are:
VR=120 V
VL=180 V
VC=120 V
Therefore, the correct answer is:
Option D: 120,180,120 V
Q 121PhysicsSection A • MCQheat and thermodynamics
+3 / -1
A vessel containing 1 mole of O2 gas (molar mass 32) at temperature T. The pressure of the gas is p. An identical vessel containing one mole of He gas (molar mass 4) at temperature 4T has a pressure of
A
p/8
B
p
C
4p
D
8p
Official Correct Answer:Option (C)
Step-by-Step Solution:
To determine the pressure of the helium (He) gas in the identical vessel, we can use the ideal gas law:
PV=nRT
Given that both vessels are identical, they have the same volume, V. Also, each vessel contains one mole of gas, so n=1 for both cases. Let's first express the pressure p of the oxygen (O2) gas in terms of the given conditions:
For the oxygen gas:
pV=nRT
Substituting the given values:
pV=(1 mole)⋅R⋅T
Therefore,
pV=RT
Now, consider the helium gas in the other vessel at temperature 4T. According to the ideal gas law:
PHeV=nRTHe
Here, THe=4T. Substituting the known values:
PHeV=(1 mole)⋅R⋅(4T)
Therefore,
PHeV=4RT
Since pV=RT from our earlier equation for the oxygen gas, we can substitute RT with pV in the helium pressure equation:
PHeV=4(pV)
Dividing both sides by V to isolate PHe:
PHe=4p
Therefore, the pressure of the helium gas at temperature 4T is 4p.
Thus, the correct answer is:
Option C: 4p
Q 122PhysicsSection A • MCQray optics
+3 / -1
A thin plano-convex lens of focal length f is split into two halves one of the halves is shifted along the optical axis. The separation between object and image formed by one of the half-lenses is 2.4 and the magnification of same lens is 2. If f and d be the focal length of the lens and separation between the two halves respectively then
∴∴⇒d(d−0.8)=0d=0.8m1.6−0.81+0.8+0.81=f10.531 or f=0.53m
Q 123PhysicsSection A • MCQwaves
+3 / -1
The fundamental frequency of an open organ pipe is 600Hz. The first overtone of this pipe has same frequency as first overtone of a closed organ pipe. If speed of sound is 330m/s, then the length of a closed organ pipe is
A
21 cm
B
37 cm
C
31 cm
D
80 cm
Official Correct Answer:Option (A)
Step-by-Step Solution:
To solve this problem, we need to understand the relationship between the frequencies of open and closed organ pipes and how their lengths are connected to these frequencies.
Firstly, let’s consider the open organ pipe. The fundamental frequency of an open organ pipe is given by:
f1=2L1v
where f1=600Hz is the fundamental frequency, v=330m/s is the speed of sound, and L1 is the length of the open organ pipe.
Hence:
600=2L1330
Solving for L1, we get:
L1=2×600330=1200330=0.275m=27.5cm
For the open organ pipe, the first overtone frequency will be:
f2=2L12v=L1v=0.275330m=1200Hz
Now, considering the closed organ pipe, the first overtone frequency for the closed organ pipe (which corresponds to the third harmonic) is given by:
f2′=4L23v
We are given that the first overtone of the open organ pipe (which is 1200Hz) is equal to the first overtone of the closed organ pipe. Hence:
1200=4L23×330
Solving for L2, we get:
1200=4L2990
Rearranging:
4L2=1200990
L2=4800990m=0.20625m=20.625cm
Given the options, there appears to be a minor discrepancy. However, the closest value is:
Option A: 21 cm
Q 124PhysicsSection A • MCQmotion
+3 / -1
A boat crosses a river from part A to part B, which are just on the opposite side. The speed of the water. vω and the of boat is vB relative to still water. Assume vB=2vω. What is the time taken by the boat, if it has to cross the river directly on the AB line (D= width of the river) ?
A
3vB2D
B
2vB3D
C
2vBD
D
vB2D
Official Correct Answer:Option (D)
Step-by-Step Solution:
In the following figure, we have
vBsinθ=vw
sinθ=vBvw=21⇒θ=45∘(∵vB=2vw)
Time to cross the river,
t=vBcosθD=vBcos45∘D=vB2D
Q 125PhysicsSection A • MCQlaws of motion
+3 / -1
The masses of block A and B are m and M, respectively. Between A and B, there is a constant frictional force F and B can slide on a smooth horizontal surface. A is set in motion with velocity 3v0 while B is at rest. What is the distance moved by A relative to B before they move with the same velocity?
A
F(m−M)mMv02
B
18F(m−M)Mv02
C
9F(m+M)mMv02
D
2F(m+M)9mMv02
Official Correct Answer:Option (D)
Step-by-Step Solution:
Consider the FBD as given below.
Equations of motion,
aA=mF( in −x direction )aB=MF( in +x direction )
Thus, we have, relative accleration of A w.r.t. B as
Initial relative velocities of A w.r.t B,uAB=3v0 using equation v2−u2+2as,
0⇒s=9v02−Mm2F(M+m)s=2F(M+m)9Mmv02
Distance moved relative to B,SAB=2F(M+m)9Mmv02
Q 126PhysicsSection A • MCQwaves
+3 / -1
When a string is divided into four segments of l1,l2,l3 and l4. The fundamental frequencies of these three segments are v1,v2,v3 and v4, respectively. The original fundamental frequency (v) of the string is
A
v=v1+v2+v3+4
B
v=v1+v2+v3+v4
C
1/v=1/v1+1/v2+1/v3+1/v4
D
v1=v11+v21+v31+v41
Official Correct Answer:Option (C)
Step-by-Step Solution:
The fundamental frequency of a string is inversely proportional to its length. So, if the string is divided into four segments of lengths l1,l2,l3 and l4, then the fundamental frequencies of these segments will be inversely proportional to their lengths.
Let the original length of the string be L. Then, we have:
l1+l2+l3+l4=L
The fundamental frequency of the original string is given by:
v=2L1μT
where T is the tension in the string and μ is the mass per unit length of the string.
The fundamental frequencies of the four segments are given by:
v1=2l11μT
v2=2l21μT
v3=2l31μT
v4=2l41μT
Adding these equations, we get:
v1+v2+v3+v4=21μT(l11+l21+l31+l41)
Now, using the equation l1+l2+l3+l4=L, we can write:
l11+l21+l31+l41=l1l2l3l4L
Substituting this into the previous equation, we get:
v1+v2+v3+v4=21μTl1l2l3l4L
Since v=2L1μT, we can write:
v1+v2+v3+v4=l1l2l3l4vL
Therefore, the correct answer is:
v1=v11+v21+v31+v41
This is option C.
Q 127PhysicsSection A • MCQray optics
+3 / -1
A vessel is half filled with a liquid of refractive index μ. The other half of the vessel is filled with an immiscible liquid of refractive index 2μ. The apparent depth of the vessel is 50% of the actual depth. Then μ is
A
1.4
B
1.5
C
1.6
D
1.25
Official Correct Answer:Option (B)
Step-by-Step Solution:
Let's denote the actual depth of the vessel as d. Given that the vessel is half-filled with one liquid and the other half with the second liquid, each liquid fills a depth of 2d.
Let the refractive index of the first liquid be μ and the refractive index of the second liquid be 2μ.
The formula to find the apparent depth due to a single layer of liquid is:
Apparent Depth=Refractive IndexActual Depth
First, we find the apparent depth for each segment of the vessel:
For the layer with refractive index μ:
Apparent Depth1=μ2d
For the layer with refractive index 2μ:
Apparent Depth2=2μ2d
The total apparent depth is the sum of the apparent depths of both layers:
Total Apparent Depth=Apparent Depth1+Apparent Depth2
Total Apparent Depth=μ2d+2μ2d
Total Apparent Depth=2μd+4μd
Total Apparent Depth=4μ2d+d
Total Apparent Depth=4μ3d
We are given that the apparent depth of the vessel is 50% of the actual depth. Therefore:
4μ3d=2d
We solve for μ by isolating it on one side of the equation. Multiply both sides by 4μ:
3d=2dμ
Divide both sides by 2d:
μ=23
μ=1.5
So, the correct option is:
Option B: 1.5
Q 128PhysicsSection A • MCQwave optics
+3 / -1
In a YDSE, the light of wavelength λ=5000Ao is used, which emerges in phase from two slits at a distance d=3×10−7m apart. A transparent sheet of thickness t=1.5×10−7m and refractive index μ=1.25 is placed over one of the slits. What is the new angular position of the central maxima of the interference pattern, from the centre of the screen? Find the value of y.
A
7.2,2dD(μ−1)t
B
7.2,dD(μ−1)t
C
6.2,dD(μ−1)t
D
5.2,d2D(μ+1)t
Official Correct Answer:Option (B)
Step-by-Step Solution:
On introduction of a transparent sheet,
Δx=(μ−1)t
if the central maxima occupies position of the nth fringe, then (μ−1)t=nλ=dsinθ
⇒sinθ=d(μ−1)t=3×10−7(1.25−1)×1.5×10−7=0.125
Therefore, central maxima has angular position, θ=sin−1(0.125)=7.18∘≈7.2∘
for small angles, sinθ≈tanθ
tanθ∴Dy=Dy=d(μ−1)t⇒y=dD(μ−1)t
Q 129PhysicsSection A • MCQcurrent electricity
+3 / -1
The power dissipated in the circuit shown in the figure 40W. The value of R is.
The wavelength of two waves are 40 and 42cm respectively. If the temperature of the room is 20∘C then what will be the number of beats produced per second by these waves. When the speed of sound at 0∘C is 332m/s ?
A
34
B
38
C
44
D
None of these
Official Correct Answer:Option (B)
Step-by-Step Solution:
Beats will be formed as the wavelengths (hence frequencies) are similar.