Official NTA Question PaperFull Solved Paper2022Paper 2
JEE Advanced 2022 Paper 2 Question Paper with Solutions
Official solved question paper for Joint Entrance Examination (Advanced). Review all 54 questions, official answer keys, and detailed step-by-step solutions below, or attempt online with timer and negative marking.
(1) Magnetic Field Due to Straight Current Carrying Wire :
B=4πrμ0i(sinα+sinβ)
Direction of B :
Note :-
On the axis of the wire magnetic field = 0.
Case 1 :
Infinite long wire (Very Long wire) :
α,β→90∘
∴B=4πrμ0i(sin90∘+sin90∘)
=4πrμ0i(1+1)
=2πrμ0i
Graph :
Case 2 :
One end is at infinite and other end is in front.
Here α=90∘ and β=0∘
B=4πrμ0i(sin90∘+sin0∘)
=4πrμ0i
Case 3 :
When drawn perpendicular from P don't lie on the wire
Here, magnetic field at point P is,
B=4πrμ0i(sinα−sinβ)
(2) Magnetic Field Due to Half Loop or Semicircle :
Half loop means 21 turn. So, N = 21.
Magnetic field at centre O,
∴ B at centre =2Rμ0×21×i=4Rμ0i
Here,
Here, N=21
i = Amount of current flowing through loop
R = Radius of half loop
Direction of B found by right hand thumb rule. Curl your right hand's finger in the direction of current then thumb gives direction of magnetic field on axis as well as entire plane.
(3) Magnetic Field Due to Quarter Loop :
Quarter loop means 41 turn. So, N = 41.
Magnetic field at O,
∴ B at centre =2Rμ0×41×i=8Rμ0i
Here,
Here, N=41
i = Amount of current flowing through loop
R = Radius of quarter loop
Direction of B found by right hand thumb rule. Curl your right hand's finger in the direction of current then thumb gives direction of magnetic field on axis as well as entire plane.
Q 2PhysicsSection B • Numericalunits and measurements
+3 / -1
In a particular system of units, a physical quantity can be expressed in terms of the electric charge e, electron mass me, Planck's constant h, and Coulomb's constant k=4πϵ01, where ϵ0 is the permittivity of vacuum. In terms of these physical constants, the dimension of the magnetic field is [B]=[e]α[me]β[h]γ[k]δ. The value of α+β+γ+δ is _______.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 4
Q 3PhysicsSection B • Numericalcurrent electricity
+3 / -1
Two resistances R1=XΩ and R2=1Ω are connected to a wire AB of uniform resistivity, as shown in the figure. The radius of the wire varies linearly along its axis from 0.2mm at A to 1mm at B. A galvanometer (G) connected to the center of the wire, 50cm from each end along its axis, shows zero deflection when A and B are connected to a battery. The value of X is ____________.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 5
Official Correct Answer:5
Step-by-Step Solution:
According to the given condition wire is having different cross-section at two junction. (Frustum shaped conducter)
Q 4PhysicsSection B • Numericalsimple harmonic motion
+3 / -1
On a frictionless horizontal plane, a bob of mass m=0.1kg is attached to a spring with natural length l0=0.1m. The spring constant is k1=0.009Nm−1 when the length of the spring l>l0 and is k2=0.016Nm−1 when l<l0. Initially the bob is released from l=0.15m. Assume that Hooke's law remains valid throughout the motion. If the time period of the full oscillation is T=(nπ)s, then the integer closest to n is __________.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 6
A disk of radius R with uniform positive charge density σ is placed on the xy plane with its center at the origin. The Coulomb potential along the z-axis is
V(z)=2ϵ0σ(R2+z2−z).
A particle of positive charge q is placed initially at rest at a point on the z axis with z=z0 and z0>0. In addition to the Coulomb force, the particle experiences a vertical force F=−ck^ with c>0. Let β=qσ2cϵ0.
Which of the following statement(s) is(are) correct?
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
V(z)=2ε0σ(R2+z2−z)
U(z)net=2ε0σq(R2+z2−z)+cz
=c[2cε0σq(R2+z2−z)+z]
When, z=0 and β=1/4
U(z) net =c(4R)=4Rc
When, z=z0=725R and; B=41
U(z) net =C[4×726R−3×725R]=729Rc
When, z=z0=73R and β=41
U(z) net =3Rc
When, Z=3R and β=41
U(z)nt=2.887Rc
As per option (A), particle reaches at origin with the KE
dzd(U)z=0 at z=73R
So, at β=41 and z=73R
Uz( net )=7Rc=2.645Rc
Similarly, for option (B),
U(z) net at z=3R the kinetic energy at origin
will become negative and mearly equal to 3Rc
Also, for option (C)
U(z) net at Z=3R>U(z) net at z=73R
Particle will return to z0
As per option D,(β>1 and z0>0)Uz( net ) increases continuously with Z. So, particle reaches the origin.
Q 6PhysicsSection B • Numericalwave optics
+4 / -2
A double slit setup is shown in the figure. One of the slits is in medium 2 of refractive index n2. The other slit is at the interface of this medium with another medium 1 of refractive index n1(=n2). The line joining the slits is perpendicular to the interface and the distance between the slits is d. The slit widths are much smaller than d. A monochromatic parallel beam of light is incident on the slits from medium 1. A detector is placed in medium 2 at a large distance from the slits, and at an angle θ from the line joining them, so that θ equals the angle of refraction of the beam. Consider two approximately parallel rays from the slits received by the detector.
Which of the following statement(s) is(are) correct?
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
$
\tan \theta =\frac{\mathrm{AB}}{d}$
And, $
\mathrm{AB} =d \tan \theta $ ........ (i)
$
\mathrm{BC} =\mathrm{AB} \sin \alpha $
$
=d \tan \theta \sin \alpha $
$
\mathrm{AD} =\mathrm{AB} \sin \theta
$
Path difference in vacuum
ΔxΔx=n1BC−n2AD=n1(AB)sinα−n2(ABsinθ)
Hence, AB(n1sinα−n2sinθ)=0
Q 7PhysicsSection B • Numericalelectrostatics
+4 / -2
In the figure, the inner (shaded) region A represents a sphere of radius rA=1, within which the electrostatic charge density varies with the radial distance r from the center as ρA=kr, where k is positive. In the spherical shell B of outer radius rB, the electrostatic charge density varies as ρB=r2k. Assume that dimensions are taken care of. All physical quantities are in their SI units.
Which of the following statement(s) is(are) correct?
$
\mathrm{Q}_{\text {total }}=\pi k r_A^4+4 \pi k\left(\frac{9}{4}-1\right) $
$
=6 \pi k ' in math mode at position 99: …\varepsilon_0}̲
<br><br>$
\te…" style="color:#cc0000">\mathrm{~V}=\frac{1}{4 \pi \varepsilon_0}\left(\frac{6 \pi k}{r_B}\right)=\frac{k}{\varepsilon_0} $
<br><br>$
\text { Hence, } \quad \mathrm{V}=\frac{k}{\varepsilon_0} $
<br><br>(C) If
$
r_B =2 $
<br><br>$
\mathrm{Q}_{\text {total }} =13 \pi K$
<br><br>(D) If $
r_B =5 / 2 $
<br><br>$
Q_{\text {total }} =22 \pi k $
<br><br>$
E =\frac{1}{4 \pi \varepsilon_0} \frac{(22 \pi k)}{25} \times 4 $
<br><br> \Rightarrow $E =\frac{22 k}{25 \varepsilon_0}$
Q 8PhysicsSection B • Numericalproperties of matter
+4 / -2
A bubble has surface tension S. The ideal gas inside the bubble has ratio of specific heats γ=35. The bubble is exposed to the atmosphere and it always retains its spherical shape. When the atmospheric pressure is Pa1, the radius of the bubble is found to be r1 and the temperature of the enclosed gas is T1. When the atmospheric pressure is Pa2, the radius of the bubble and the temperature of the enclosed gas are r2 and T2, respectively.
Which of the following statement(s) is(are) correct?
Area of the cross-section of a wire is measured using a screw gauge. The pitch of the main scale is 0.5mm. The circular scale has 100 divisions and for one full rotation of the circular scale, the main scale shifts by two divisions. The measured readings are listed below.
Measurement condition
Main scale reading
Circular scale reading
Two arms of gauge touching each other without wire
0 division
4 divisions
Attempt-1: With wire
4 divisions
20 divisions
Attempt-2: With wire
4 divisions
16 divisions
What are the diameter and cross-sectional area of the wire measured using the screw gauge?
In a radioactive decay chain reaction, 90230Th nucleus decays into 84214Po nucleus. The ratio of the number of α to number of β−particles emitted in this process is ________.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 2
Official Correct Answer:2
Step-by-Step Solution:
To solve this problem, we need to analyze the changes in the atomic number and mass number during the decay chain reaction from 90230Th (Thorium) to 84214Po (Polonium). Let's denote the number of alpha particles emitted by nα and the number of beta-minus particles emitted by nβ−.
First, consider the changes in the mass number (A) and atomic number (Z). For alpha decay, which emits an α particle (24He), the mass number decreases by 4, and the atomic number decreases by 2. For beta-minus decay, which emits a β− particle (an electron, e−), the atomic number increases by 1, but the mass number remains unchanged.
The initial and final nuclei are given as:
Initial: 90230Th
Final: 84214Po
The changes in the mass number (A) and atomic number (Z) are:
Change in mass number (A): 230−214=16
Change in atomic number (Z): 90−84=6
Since each alpha particle decreases the mass number by 4 and the atomic number by 2, if nα is the number of alpha particles emitted, we have:
ΔA=4nα
ΔZα=2nα
From the given changes, we can write:
4nα=16⇒nα=416=4
The contribution to the change in atomic number due to the alpha particles is:
ΔZα=2×4=8
However, since the change in atomic number is 6, the number of beta-minus particles emitted must account for the difference:
ΔZ−ΔZα=nβ−⇒6−8=nβ−⇒nβ−=2 (increase)
Note that an increase of 2 units due to β− (beta-minus decay) particles means:
ΔZβ−=nβ−=2
Thus the number of β− particles emitted is 2.
Therefore, the ratio of the number of α particles to the number of β− particles emitted is:
nβ−nα=24=2
So, the ratio is 2.
Q 11PhysicsSection B • Numericalsimple harmonic motion
+3 / -1
A particle of mass 1kg is subjected to a force which depends on the position as F=−k(x^+y^)kgms−2 with k=1kgs−2. At time t=0, the particle's position r=(21^+2^)m and its velocity v=(−2^+2^+π2k^)ms−1. Let vx and vy denote the x and the y components of the particle's velocity, respectively. Ignore gravity. When z=0.5m, the value of (xvy−yvx) is __________ m2s−1.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 3
Consider a configuration of n identical units, each consisting of three layers. The first layer is a column of air of height h=31cm, and the second and third layers are of equal thickness d=23−1cm, and refractive indices μ1=23 and μ2=3, respectively. A light source 0 is placed on the top of the first unit, as shown in the figure. A ray of light from 0 is incident on the second layer of the first unit at an angle of θ=60∘ to the normal. For a specific value of n, the ray of light emerges from the bottom of the configuration at a distance l=38cm, as shown in the figure. The value of n is ________.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 4
Official Correct Answer:4
Step-by-Step Solution:
x1=31×tan60=31cm
By Snell's law
1×sin60=23sinθ2⇒θ2=45o∴x2=d
Again, by applying Snell's law
23×21=3×sinθ3⇒θ2=30∘∴x3=3d
Also x1+x2+x3=31+d+3d=31+(23−1)+233−1=232+(3−3)+3−1=234x1+x2+x3=32cmAnd,η=x1+x2+x3lη=2/38/3=4η=4
Q 13PhysicsSection B • Numericalheat and thermodynamics
+4 / -2
In the given P−V diagram, a monoatomic gas (γ=35) is first compressed adiabatically from state A to state B. Then it expands isothermally from state B to state C. [Given: (31)0.6≃0.5,ln2≃0.7 ].
Which of the following statement(s) is(are) correct?
An object and a concave mirror of focal length f=10cm both move along the principal axis of the mirror with constant speeds. The object moves with speed V0=15cms−1 towards the mirror with respect to a laboratory frame. The distance between the object and the mirror at a given moment is denoted by u. When u=30cm, the speed of the mirror Vm is such that the image is instantaneously at rest with respect to the laboratory frame, and the object forms a real image. The magnitude of Vm is _________ cms−1.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 3
A charge q is surrounded by a closed surface consisting of an inverted cone of height h and base radius R, and a hemisphere of radius R as shown in the figure. The electric flux through the conical surface is 6ϵ0nq (in SI units). The value of n is _______.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 3
A flat surface of a thin uniform disk A of radius R is glued to a horizontal table. Another thin uniform disk B of mass M and with the same radius R rolls without slipping on the circumference of A, as shown in the figure. A flat surface of B also lies on the plane of the table. The center of mass of B has fixed angular speed ω about the vertical axis passing through the center of A. The angular momentum of B is nMωR2 with respect to the center of A. Which of the following is the value of n ?
A
2
B
5
C
27
D
29
Official Correct Answer:Option (B)
Step-by-Step Solution:
Angular momentum of B with respect to center of A
L=LCM+LBody about CM =M(2R)2ωk^+2MR2(ωbody )k^=M(2R)2ωk^+2MR2(2ω)k^=5MR2ωk^
Comparing the magnitude with nMωR2
n=5
Q 17PhysicsSection B • Numericalcurrent electricity
+4 / -2
In Circuit-1 and Circuit- 2 shown in the figures, R1=1Ω,R2=2Ω and R3=3Ω.
P1 and P2 are the power dissipations in Circuit-1 and Circuit-2 when the switches S1 and S2 are in open conditions, respectively.
Q1 and Q2 are the power dissipations in Circuit-1 and Circuit-2 when the switches S1 and S2 are in closed conditions, respectively.
Which of the following statement(s) is(are) correct?
Q 18PhysicsSection A • MCQdual nature of radiation
+3 / -1
When light of a given wavelength is incident on a metallic surface, the minimum potential needed to stop the emitted photoelectrons is 6.0V. This potential drops to 0.6V if another source with wavelength four times that of the first one and intensity half of the first one is used. What are the wavelength of the first source and the work function of the metal, respectively? [Take ehc=1.24×10−6JmC−1.]
During racemisation of optically active compound, disorder increases and hence, entropy increases.
(D) For [Ni(H2O)6]2++3en→[Ni(en)3]+3+6H2O,
Entropy increases when bidentate ligands replace monodentate ligands due to increase in the number of molecules on the product side.
Hence, (B, C, D) are correct.
Q 20ChemistrySection B • Numericalp block elements
+4 / -2
The compound(s) which react(s) with NH3 to give boron nitride (BN) is(are)
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
The compound(s) which react with NH3 to form Boron nitride (BN) is/are:
(A) Amorphous B+NH3 Tempreature ⟶ Very high BN+H2
(B) B2H6+NH3⟶ High Temp. (BN)x
(C) B2O3+2NH3⟶900∘C2BN+3H2O
(D) HBF4+NH3⟶[NH4⊕][BF4⊖]
Hence, (A,B,C) are correct
Q 21ChemistrySection A • MCQsolid state
+3 / -1
Atom X occupies the fcc lattice sites as well as alternate tetrahedral voids of the same lattice. The packing efficiency (in %) of the resultant solid is closest to
A
25
B
35
C
55
D
75
Official Correct Answer:Option (B)
Step-by-Step Solution:
Atom X occupies FCC lattice sites as well as alternate tetrahedral voids of FCC.
In FCC, tetrahedral voids are 8 (in a unit cell)
Hence
Atom X in a unit cell (FCC lattice sites) =8×81+6×21=4
Atom X in a unit cell (in T.V.) =21×8=4
Total atom X in one unit cell =8
For relation between a and r, since T.V. forms at 41 th of body diagonal,
4a3=2r⇒a=38r
Packing efficiency
=a38×34πr3×100=(38r)38×34πr3×100≃35%
Q 22ChemistrySection A • MCQp block elements
+3 / -1
The reaction of Pb(NO3)2 and NaCl in water produces a precipitate that dissolves upon the addition of HCl of appropriate concentration. The dissolution of the precipitate is due to the formation of
A
PbCl2
B
PbCl4
C
[PbCl4]2−
D
[PbCl6]2−
Official Correct Answer:Option (C)
Step-by-Step Solution:
Pb2+ on reaction with Cl−, produces white precipitate of PbCl2
Pb2++2Cl−⟶PbCl2↓
(White)
This precipitate is soluble in concentrated hydrochloric acid due to formation of tetrachloroplumbate (II) ion
PbCl2↓+2Cl−⟶[PbCl4]2−
Q 23ChemistrySection B • Numericalpolymers
+4 / -2
Among the following, the correct statement(s) about polymers is(are)
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
(A) Polymerization of chloroprene gives synthetic rubber.
(B) Teflon is manufactured by heating tetrafluoroethene with a free radical or persulphate catalyst at hight pressure.
(C) Polyvinyl chloride (PVC) is a thermoplastic polymer and used in making hand bags, vinyl flooring and water pipes.
(D) Ethene at 350-570 K temperature and 1000-2000 atm pressure in the presence of a peroxide initiator yields low density polythene.
Q 24ChemistrySection B • Numericalhydrocarbons
+3 / -1
The total number of chiral molecules formed from one molecule of P on complete ozonolysis (O3,Zn/H2O) is _________.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 2
Official Correct Answer:2
Step-by-Step Solution:
Q 25ChemistrySection A • MCQp block elements
+3 / -1
The reaction of HClO3 with HCl gives a paramagnetic gas, which upon reaction with O3 produces
A
Cl2O
B
ClO2
C
Cl2O6
D
Cl2O7
Official Correct Answer:Option (C)
Step-by-Step Solution:
HClO3 reacts with HCl according to the following equation,
2HClO3+2HCl⟶2ClO2+Cl2+2H2O
ClO2 molecule is paramagnetic, as it contains odd number of electrons.
2ClO2+2O3⟶Cl2O6+2O2
Q 26ChemistrySection B • Numericalsome basic concepts of chemistry
+4 / -2
To check the principle of multiple proportions, a series of pure binary compounds (PmQn) were analyzed and their composition is tabulated below. The correct option(s) is(are)
Compound
Weight % of P
Weight % of Q
1
50
50
2
44.4
55.6
3
40
60
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
(A) If emperical formula of compound 3 is P3Q4 then its molar ratio will be 340:460
=340×604=1816=0.88
If empirical formula of compound 2 is P3Q5, then its molar ratio
=244.4:555.6=244.4×55.65=2
Since molar ratio of both the compound is not equal
So, option (A) is not correct.
(B) If empirical formula of compound 3 is P3Q2, i.e.,
MP40:MQ60=23⇒MP40×60MQ=23
⇒6MP4MQ⇒MPMQ=23=23×46=49
and MP=20 (given)
So, 20MQ=49
MQ=49×265MQ=45
So, option (B) is correct.
(C) If empirical formula of compound 2 is PQ, So the molar ratio is
144.4:155.6=55.644.4=0.79∼0.8
Empirical formula of compound 1 is P5Q4
so the molar ratio is 550:450.
=550×504=54=0.8
Since, molar ratio of both the compound is equal hence, state (C) is correct.
So, option (C) is correct.
(D) MP=70,MQ=35
Molar ratio of compound 1 is
MP50:MQ50=7050:3550=7050×5035=21
Hence, empirical formula of compound PQ2.
So, option (D) is incorrect.
Q 27ChemistrySection B • Numericald and f block elements
+3 / -1
Thermal decomposition of AgNO3 produces two paramagnetic gases. The total number of electrons present in the antibonding molecular orbitals of the gas that has the higher number of unpaired electrons is ____________.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 6
Official Correct Answer:6
Step-by-Step Solution:
2AgNO3(s)⟶Δ2Ag(s)+2NO2(g)+O2(g)
Both the NO2 and O2 gases are paramagnetic. NO2(g) has 1 unpaired electron and O2(g) has 2 unpaired electrons.
According to MOT,
∴ Molecular orbital configuration of O2 (16 electrons) is
Nb = Number of electrons in bonding molecular orbital
Na= Number of electrons in anti bonding molecular orbital
(1) upto 14 electrons, molecular orbital configuration is
Here Na = Anti bonding electrons = 4 and Nb = 10
(2) After 14 electrons to 20 electrons molecular orbital configuration is - - -
Here Na = 10
and Nb = 10
Q 28ChemistrySection B • Numericalionic equilibrium
+3 / -1
Concentration of H2SO4 and Na2SO4 in a solution is 1M and 1.8×10−2M, respectively. Molar solubility of PbSO4 in the same solution is X×10−YM (expressed in scientific notation). The value of Y is ________.
[Given: Solubility product of PbSO4(Ksp)=1.6×10−8. For H2SO4,Kal is very large and Ka2=1.2×10−2]
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 6
Official Correct Answer:6
Step-by-Step Solution:
Given,
Conentration of H2SO4=1M
Conentration of Na2SO4 = 1.8×10−2M
From the above two equations, we get
[H+]=1M and [SO42−]=1.8×10−2
Kc=11.8×10−2×1=1.8×10−2
and it is given that Ka2(Qc)=1.2×10−2M
Since, Ka2 (i.e., Qc ) <Kc
∴ Rather than dissociation of HSO4−into H+and SO42− ions, association between already present H+and SO42− will take place.
Assuming ' x ' mol/L of SO42− and H+combines to form HSO4−
Ka2=[HSO4−][H+][SO42−]1.2×10−2=(1+x)(1−x)(1.8×10−2−x)∵x<<1, so (1+x)≈1 and (1−x)≈11.2×10−2=1.8×10−2−xx=(1.8×10−2)−(1.2×10−2)x=0.6×10−2M So, [SO42−]=1.8×10−2−x[SO42−]=(1.8×10−2)−(0.6×10−2)[SO42−]=1.2×10−2M
Given, Ksp=1.6×10−8
∴y(1.2×10−2+y)=1.6×10−8
Since, y<<1, So 1.2×10−2+y≈1.2×10−2
So, y×1.2×10−2=1.6×10−8
⇒y=1.2×10−21.6×10−8
⇒y=1.33×10−6
$
X \times 10^{-Y} \mathrm{M} =1.33 \times 10^{-6} \mathrm{M}
$
So, Y=6
Hence, the value of Y is 6 .
Q 29ChemistrySection B • Numericalhydrocarbons
+3 / -1
The number of isomeric tetraenes (NOT containing sp-hybridized carbon atoms) that can be formed from the following reaction sequence is ___________.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 2
Official Correct Answer:2
Step-by-Step Solution:
Q 30ChemistrySection B • Numericalhydrocarbons
+3 / -1
The number of −CH2− (methylene) groups in the product formed from the following reaction sequence is _________.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 0
Official Correct Answer:0
Step-by-Step Solution:
Q 31ChemistrySection B • Numericalhydrocarbons
+4 / -2
Considering the following reaction sequence, the correct statement(s) is(are)
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
Compound (S) can not decolorizes bromine water.
R2Cd is a less reactive nucleophile so reaction stops at carbonyl group.
Q 32ChemistrySection B • Numericalisolation of elements
+4 / -2
The correct option(s) related to the extraction of iron from its ore in the blast furnace operating in the temperature range 900−1500K is(are)
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
(A) Limestone is added to remove silica as impurity.
(B) Pig iron obtained from blast furnace contains 4% carbon and many other impurities (eg. S, P, Si, Mn) in
small amount.
(C) Coke (C) converts CO2 in CO.
C+CO2→2CO
(D) Exhaust gases consist of CO and CO2.
Hence, (A, B, C) are correct.
Q 33ChemistrySection B • Numericald and f block elements
+3 / -1
The reaction of Xe and O2F2 gives a Xe compound P. The number of moles of HF produced by the complete hydrolysis of 1mol of P is __________.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 4
Official Correct Answer:4
Step-by-Step Solution:
Xe+2O2F2→(P)XeF4+2O2
(P)6XeF4+12H2O⟶4Xe+2XeO3+24HF+3O2
So, from the above reaction, it is clear that 6 moles of XeF4 produces 24 moles of HF.
So, 1 mole of XeF4 will produce 624 moles of HF, i.e., 4 moles of HF.
Q 34ChemistrySection B • Numericalelectrochemistry
+3 / -1
Consider the strong electrolytes ZmXn,UmYp and VmXn. Limiting molar conductivity ( Λ0 ) of UmYp and VmXn are 250 and 440Scm2mol−1, respectively. The value of (m+n+p) is
Given:
Ion
Zn+
Up+
Vn+
Xm−
Ym−
λ0(Scm2mol−1)
50.0
25.0
100.0
80.0
100.0
λ0 is the limiting molar conductivity of ions
The plot of molar conductivity ( Λ ) of ZmXnvsc1/2 is given below.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 7
Now, substituting the value of m is eqn (1), we get
10⇒10⇒8⇒p⇒p=m+4p=2+4p=4p=48=2=22
So, m+n+p=2+3+2
⇒m+n+p=7
Hence, the required value of m+n+p is 7 .
Q 35ChemistrySection B • Numericalsolutions
+3 / -1
An aqueous solution is prepared by dissolving 0.1mol of an ionic salt in 1.8kg of water at 35∘C. The salt remains 90% dissociated in the solution. The vapour pressure of the solution is 59.724mm of Hg. Vapor pressure of water at 35∘C is 60.000mm of Hg. The number of ions present per formula unit of the ionic salt is _________.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 5
Official Correct Answer:5
Step-by-Step Solution:
Vapour pressure of solution (PA)=59.724mm of Hg
Vapour pressure of pure water (PA∘)=60.000mm of Hg
Also, 0.1mol of an ionic solid is dissolved in 1.8kg of water and salt remains 90% dissocated in the solution.
So, total number of moles =0.01+0.09a of non-volatile particles.
Now, mass of water =1.8kg=1.8×1.8×1000g
Molar mass of water =18g
Moles of water =181.8×1000=100 moles
Using the colligative property, relative lowering in vapour pressure,
PA∘PA∘−PA=xA
⇒6060−59.724=1000.01+0.09a
⇒ $
\frac{0.276}{60} =\frac{0.01+0.09 a}{100} $
⇒ $
\frac{27.6}{60} =0.01+0.09 a $
⇒ $
0.46 =0.01+0.09 a $
⇒ $
0.09 a =0.45 $
⇒ $
a =\frac{0.45}{0.89} $
⇒ $
a =5
$
So, the number of ions present per formula unit of the ionic salt is 5 .
Q 36ChemistrySection A • MCQbiomolecules
+3 / -1
Treatment of D-glucose with aqueous NaOH results in a mixture of monosaccharides, which are
A
B
C
D
Official Correct Answer:Option (C)
Step-by-Step Solution:
Q 37MathematicsSection A • MCQmatrices and determinants
Box-II contains 24 red, 9 blue and 15 green balls,
Box-III contains 1 blue, 12 green and 3 yellow balls,
Box-IV contains 10 green, 16 orange and 6 white balls.
A ball is chosen randomly from Box-I; call this ball b. If b is red then a ball is chosen randomly from Box-II, if b is blue then a ball is chosen randomly from Box-III, and if b is green then a ball is chosen randomly from Box-IV. The conditional probability of the event 'one of the chosen balls is white' given that the event 'at least one of the chosen balls is green' has happened, is equal to
Let G be a circle of radius R>0. Let G1,G2,…,Gn be n circles of equal radius r>0. Suppose each of the n circles G1,G2,…,Gn touches the circle G externally. Also, for i=1,2,…,n−1, the circle Gi touches Gi+1 externally, and Gn touches G1 externally. Then, which of the following statements is/are TRUE?
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
Here if we add center of circles G1, G2, G3 ....... Gn, then we get a polygon of n sides.
From figure you can see one side of polygon makes angle θ with the center.
∴ n sides make angle = nθ
We know, nθ=2π
⇒θ=n2π
Here triangle OMN is an isosceles triangle. Line joining of point O and midpoint O of MN (point A) is perpendicular to line MN and perpendicular bisector of angle θ.
∴∠MOA=2θ=nπ
From right angle triangle OMA,
sinnπ=R+rr
⇒R+r=rcosecnπ
Option A:
When n=4,
R+r=rcosec4π
⇒R+r=2r
⇒R=(2−1)r
∴ Option (A) is wrong.
Option B :
When n=5,
R+r=rcosec5π=rcosec36∘
We know, in 0 to 2π, cosecθ is decreasing.
∴cosec45∘<cosec36∘<cosec30∘
⇒2<cosec36∘<2
⇒2r<rcosec36∘<2r
⇒2r−r<rcosec36∘−r<2r−r
⇒(2−1)r<R<r
∴R<r, when n=5
∴ Option (B) is wrong.
Option C :
When n=8,
R+r=rcosec8π
cosecθ is decreasing function in 0 to 2π.
∴cosec8π>cosec4π
⇒rcosec8π>2r
⇒R+r>2r
⇒R>(2−1)r
∴ Option (C) is correct.
Option D :
When n=12, then
R+r=r(cosec12π)
⇒R+r=r×3−122 [as cosec12π=3−122]
⇒R+r=r×222(3+1)
⇒R+r=2r(3+1)
⇒R=[2(3+1)−1]r
⇒R<2(3+1)r
∴ Option (D) is correct.
Q 40MathematicsSection A • MCQlimits continuity and differentiability
Q 41MathematicsSection B • Numericalcomplex numbers
+4 / -2
Let zˉ denote the complex conjugate of a complex number z. If z is a non-zero complex number for which both real and imaginary parts of
(zˉ)2+z21
are integers, then which of the following is/are possible value(s) of ∣z∣ ?
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
Let, complex number (z)2+z21 is a new complex number w.
∴w=(z)2+z21
Now, let z=reiθ where r=∣z∣ and θ = argument
∴w=(re−iθ)2+r21(e−2iθ)
=(r2+r21)e−2iθ
=(r2+r21)(cos2θ−isin2θ)
∴ Real part of w=Re(w)=(r2+r21)cos2θ
Imaginary part of w=Im(w)=(r2+r21)(−sin2θ)
Given both Re(w) and Im(w) are integer.
∴ Let Re(w)=I1
and Im(w)=I2
∴I12+I22=(r2+r21)2=α (where α is an integer)
[Note : As I1 and I2 are integer so I12+I22 is also an integer.]
Now, (r2+r21)2=α
⇒r4+2+r41=α
⇒r8+2r4+1=r4α
⇒r8−(α−2)r4+1=0
∴r4=2.1(α−2)±(α−2)2−4.1.1
⇒r=(2(α−2)±α2−4α)41
⇒∣z∣=r=(2(α−2)±α2−4α)41
In option only positive sign is given so ignoring negative sign we get,
∣z∣=r=(2(α−2)+α2−4α)41 ....... (1)
From option (A),
∣z∣=(243+3205)41
Comparing with (1), we get
α−2=43
⇒α=45
Putting α=45 in (1), we get
∣z∣=(243+45(41))41
=(243+9×5×41)41
=(243+3205)41
∴ Option (A) is correct.
We can re-write
∣z∣=(2(α−2)+α2−4α)41
as ∣z∣=(42(α−2)+2α(α−4))41
Comparing with option (B) we get,
2(α−2)=7
⇒2α=11
⇒α=211= Integer
∴ Option (B) is incorrect.
Similarly option (C) and (D) also incorrect.
Q 42MathematicsSection B • Numericalvector algebra
+4 / -2
Let ^,^ and k^ be the unit vectors along the three positive coordinate axes. Let
Q 44MathematicsSection A • MCQpermutations and combinations
+3 / -1
Consider 4 boxes, where each box contains 3 red balls and 2 blue balls. Assume that all 20 balls are distinct. In how many different ways can 10 balls be chosen from these 4 boxes so that from each box at least one red ball and one blue ball are chosen ?
A
21816
B
85536
C
12096
D
156816
Official Correct Answer:Option (A)
Step-by-Step Solution:
Case 1 :
Among four bags from one bag 4 balls are taken. Number of ways of chosing one bag from 4 bags = 4C1
From this bag number of ways of taking 4 balls are
(a) 3 Red and 1 Blue balls, which can be chosen in 3C3×2C1 ways.
(b) 2 Red and 2 Blue balls, which can be chosen in 3C2×2C2 ways.
∴ Total number of ways of choosing this 4 balls from this bag = 4C1(3C3×2C1+3C2×2C2)
Now, two balls are taken from remaining three bags.
From each bag two balls can be taken in 3C1×2C1 ways.
So, for three bags two balls can be taken in (3C1×2C1)3 ways.
∴ Total number of ways of chosing 10 balls from these four bags
= 4C1(3C3×2C1+3C2×2C2)×(3C1×2C1)3
Case 2 :
Among four bags from two bags 3 balls are taken. Number of ways of chosing two bags from 4 bags = 4C2
From each bag, number of ways of taking 3 balls are
(a) 2 Red and 1 Blue balls, which can be chosen in 3C2×2C1 ways.
(b) 1 Red and 2 Blue balls, which can be chosen in 3C1×2C2 ways.
So, for two bags three balls can be taken in (3C2×2C1+3C1×2C2)2 ways.
∴ Total number of ways of choosing this 3 balls from this two bags = 4C2(3C2×2C1+3C1×2C2)2
Now, two balls are taken from remaining two bags.
From each bag two balls can be taken in 3C1×2C1 ways.
So, for two bags two balls can be taken in (3C1×2C1)2 ways.
∴ Total number of ways of chosing 10 balls from these four bags
= 4C2(3C2×2C1+3C1×2C2)2×(3C1×2C1)2
From Case 1 and Case 2, total number of ways of chosing 10 balls from these 4 boxes so that from each box at least one red ball and one blue ball are chosen
= 4C1(3C3×2C1+3C2×2C2)×(3C1×2C1)3
+ 4C2(3C2×2C1+3C1×2C2)2×(3C1×2C1)2
=4(5)(6)3+6(3×2+3)2(6)2=4320+17496=21816
Q 45MathematicsSection B • Numericaltrigonometric functions and equations
+4 / -2
Let PQRS be a quadrilateral in a plane, where
QR=1,∠PQR=∠QRS=70∘,∠PQS=15∘ and ∠PRS=40∘.
If ∠RPS=θ∘,PQ=α and PS=β, then the interval(s) that contain(s) the value of
4αβsinθ∘ is/are
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
Applying sine rule in △PQR,
⇒sin30∘α=sin80∘1α=2sin80∘1
Applying sine rule in △PRS,
⇒βsinθ=sin40∘β=sinθ1sin40∘
From (i) and (ii),
4αβsinθ=4⋅2sin80∘1⋅sin40∘=cos40∘1
Using cos0∘=1,cos30∘=23,cos45∘=21 and cos60∘=21
Only Options (A) and (B) are correct.
Q 46MathematicsSection B • Numericaldifferential equations
+4 / -2
For x∈R, let the function y(x) be the solution of the differential equation
dxdy+12y=cos(12πx),y(0)=0
Then, which of the following statements is/are TRUE ?
with foci at S and S1, where S lies on the positive x-axis. Let P be a point on the hyperbola, in the first quadrant. Let ∠SPS1=α, with α<2π. The straight line passing through the point S and having the same slope as that of the tangent at P to the hyperbola, intersects the straight line S1P at P1. Let δ be the distance of P from the straight line SP1, and β=S1P. Then the greatest integer less than or equal to 9βδsin2α is ________.
Answer Format:Enter numerical value rounded to the nearest integerOfficial Answer: 7
Official Correct Answer:7
Step-by-Step Solution:
From property we know, tangent and normal is bisector of the angle between focal radii.
∴ Tangent AB divides the angle ∠SPS1=α equal parts.
From another property, we know, if we draw perpendicular to the tangent on the hyperbola from two foci, then product of length of the perpendicular from foci = b2
∴l×δ=b2
Given hyperbola, 100x2−64y2=1
∴a2=100
and b2=64
∴l×δ=64 ....... (1)
From right angle triangle S1 MP we get, sin2α=βl