Official NTA Question PaperFull Solved Paper2026Morning Shift
JEE Main 2026 6th April Morning Shift Question Paper with Solutions
Official solved question paper for Joint Entrance Examination (Main). Review all 75 questions, official answer keys, and detailed step-by-step solutions below, or attempt online with timer and negative marking.
The density ρ of a uniform cylinder is determined by measuring its mass m, length l and diameter d. The measured values of m, l and d are 97.42 ± 0.02 g, 8.35 ± 0.05 mm and 20.20 ± 0.02 mm, respectively. Calculated percentage fractional error in ρ is _______.
A
0.63%
B
0.82%
C
0.72%
D
0.25%
Official Correct Answer:Option (B)
Step-by-Step Solution:
ρ=Vm=π(2d)2lm=πd2l4m
ρΔρ=mΔm+2dΔd+lΔl
ρΔρ=97.420.02+2(20.200.02)+8.350.05
ρΔρ≈0.000205+2(0.00099)+0.005988
ρΔρ≈0.000205+0.00198+0.005988≈0.008173
% error=ρΔρ×100≈0.008173×100≈0.82%
Q 2PhysicsSection A • MCQunits and measurements
+4 / -1
The potential energy of a particle changes with distance x from a fixed origin as V=x+BAx, where A and B are constants with appropriate dimensions. The dimensions of AB are _______.
A
[M1L5/2T−2]
B
[M3/2L5/2T−2]
C
[M1L2T−2]
D
[M1L7/2T−2]
Official Correct Answer:Option (D)
Step-by-Step Solution:
V=x+BAx
[B]=[x]=[L]
[V]=[x+B][A][x]
[M1L2T−2]=[L][A][L1/2]
[A]=[M1L5/2T−2]
[AB]=[M1L5/2T−2]×[L1]
[AB]=[M1L7/2T−2]
Q 3PhysicsSection A • MCQwork power and energy
+4 / -1
The rain drop of mass 1 g, starts with zero velocity from a height of 1 km. It hits the ground with a speed of 5 m/s. The work done by the unknown resistive force is _______ J. (take g = 10 m/s2)
A
−8.75
B
−8.35
C
−9.55
D
−9.98
Official Correct Answer:Option (D)
Step-by-Step Solution:
Use work-energy theorem:
Wgravity+Wresistive=ΔK
given:
m=1g=10−3kg
h=1 km=1000 m
u=0,v=5 m/s
step 1: work done by gravity
Wg=mgh=10−3×10×1000=10J
step 2: change in kinetic energy
ΔK=21mv2=21×10−3×25=0.0125J
step 3: resistive work
10+Wr=0.0125
Wr=0.0125−10=−9.9875J
Q 4PhysicsSection A • MCQlaws of motion
+4 / -1
Two blocks (P and Q) with respectively masses 2 kg and 1.5 kg are joined by a massless thread. These blocks are mounted on a frictionless pully which is fixed on the edge of a cube (S), as shown in the figure below. Block P is positioned on the top surface which has no friction and block Q is in contact with side-surface, having coefficient friction μ. The cube (S) moves towards the right with acceleration of 2g, where g is gravitational acceleration. During this movement the block P and Q remain stationary. The value of μ is _______. (take g = 10 m/s2)
A
0.33
B
0.67
C
1
D
0.5
Official Correct Answer:Option (B)
Step-by-Step Solution:
For block P, Leftward pseudo-force = mP⋅a=mP⋅2g
Rightward tension force from the thread = T
Balancing the horizontal forces on block P: T=mP⋅2g=2⋅2g=g— (1)
The cube pushes block Q to the right with a normal contact force N. The leftward pseudo-force presses it against the wall:
N=mQ⋅a=mQ⋅2g=1.5⋅2g=21.5g
Downward gravitational force = mQ⋅g=1.5g
Upward tension force = T=g (from Equation 1)
T+f=mQ⋅g
g+f=1.5g⟹f=0.5g— (2)
f=μN
0.5g=μ(21.5g)
0.5=μ⋅0.75⟹μ=0.750.5=32≈0.67
Q 5PhysicsSection A • MCQproperties of matter
+4 / -1
A lift of mass 1600 kg is supported by thick iron wire. If the maximum stress which the wire can withstand is 4×108 N/m2 and its radius is 4 mm, then maximum acceleration the lift can take is _______ m/s2. (take g = 10 m/s2 and π = 3.14)
A
2.56
B
3.89
C
4.32
D
5.16
Official Correct Answer:Option (A)
Step-by-Step Solution:
The maximum stress is the maximum force per unit area. Therefore, the maximum tension (Tmax) is:
Tmax=σmax×A
Where the cross-sectional area A=πr2.
Substitute the values:
Tmax=(4×108)×(3.14×(4×10−3)2)
Tmax=(4×108)×(3.14×16×10−6)
Tmax=64×3.14×102
Tmax=200.96×100
Tmax=20096 N
When the lift is accelerating upwards with a maximum acceleration a, the net upward force is Tmax−mg.
According to the equation of motion:
Tmax−mg=ma
Tmax=m(g+a)
Substitute the known values into the equation:
20096=1600(10+a)
Solve for a:
160020096=10+a
12.56=10+a
a=12.56−10
a=2.56 m/s2
Q 6PhysicsSection A • MCQrotational motion
+4 / -1
A solid sphere of radius 4 cm and mass 5 kg is rotating (rotation axis is passing through the centre of the sphere) with an angular velocity of 1200 rpm. It is brought to rest in 10 s by applying a constant torque. The torque applied and the number of rotations it made before it comes to rest are _______ and _______ respectively.
A
0.128π Nm, 100
B
0.0128π Nm, 50
C
0.128π Nm, 50
D
0.0128π Nm, 100
Official Correct Answer:Option (D)
Step-by-Step Solution:
Initial angular velocity, ω0=1200 rpm
Final angular velocity, ω=0 rad/s (since it is brought to rest)
Time taken to stop, t=10 s
ω0=1200×602π
ω0=20×2π=40π rad/s
Using the first equation of rotational kinematics:
ω=ω0+αt
0=40π+α(10)
10α=−40π
α=−4π rad/s2
The magnitude of angular deceleration is 4π rad/s2.
The formula for the moment of inertia of a solid sphere about an axis passing through its center is:
I=52MR2
I=52×5×(0.04)2
I=2×0.0016
I=0.0032 kg⋅m2=3.2×10−3 kg⋅m2
Using Newton's second law for rotation (magnitude of torque):
τ=I∣α∣
τ=(0.0032)×(4π)
τ=0.0128π N⋅m
τ=1.28π×10−2 N⋅m
First, find the total angular displacement (θ):
θ=(2ω0+ω)t
θ=(240π+0)×10
θ=20π×10=200π rad
Now, convert radians to the number of rotations:
N=2πθ
N=2π200π
N=100
Q 7PhysicsSection A • MCQcircular motion
+4 / -1
A smooth inclined plane ends in a vertical circular loop, as shown in the figure. A small body is released from height h as shown. If the body exerts a force of three times its weight on the plane at the highest point of circle then the height h=αR. The value of α is _______.
A
2
B
4
C
3
D
6
Official Correct Answer:Option (B)
Step-by-Step Solution:
Solution :
At the highest point of the vertical circle :
Centripetal force is provided by weight and normal reaction.
Given body exerts force three times its weight on the track.
Therefore, reaction by track on body is :
N=3mg
At highest point :
mg+N=Rmv2
mg+3mg=Rmv2
4mg=Rmv2
v2=4gR
Using conservation of mechanical energy :
Initial energy at height h :
Ei=mgh
Energy at highest point of loop :
Height of highest point above ground :
2R
Therefore,
Ef=mg(2R)+21m(4gR)
=2mgR+2mgR
=4mgR
Equating energies :
mgh=4mgR
h=4R
Comparing with :
h=αR
Therefore,
α=4
Final Answer :
4
Q 8PhysicsSection A • MCQcenter of mass
+4 / -1
The position of center of mass of three masses 2 kg, 3 kg and 15 kg placed with respect to mid point (p) of normal bisector, as shown in the figure is _______.
A
(43,1.25)
B
(43,1.0)
C
(0,0)
D
(1.25,0)
Official Correct Answer:Option (A)
Step-by-Step Solution:
Total Mass (M)=2+3+15=20 kg
Xcm=202×(−53)+3×(53)+15×0=43 cm
Ycm=202×(−25)+3×(−25)+15×(25)=2025=1.25 cm
Q 9PhysicsSection A • MCQproperties of matter
+4 / -1
The two wires A and B of equal cross-section but of different materials are joined together. The ratio of Young's modulus of wire A and wire B is 20/11. When the joined wire is kept under certain tension the elongations in the wires A and B are equal. If the length of wire A is 2.2 m, then the length of wire B is _______ m.
A
1.1
B
2.22
C
1.21
D
4.44
Official Correct Answer:Option (C)
Step-by-Step Solution:
Y=StrainStress=ΔL/LF/A
Rearranging for elongation (ΔL):
ΔL=AYFL
According to the problem, both wires are joined together and kept under the same tension,have same area, same elongation:
FA=FB=F
AA=AB=A
ΔLA=ΔLB
Substitute the expression for elongation for both wires:
A⋅YAF⋅LA=A⋅YBF⋅LB
YALA=YBLB
We need to find the length of wire B (LB). Rearranging the equation gives:
LB=LA×YAYB
YBYA=1120⟹YAYB=2011
LA=2.2 m
Substitute these values into the equation for LB:
LB=2.2×2011
LB=2024.2
LB=1.21 m
Q 10PhysicsSection A • MCQheat and thermodynamics
+4 / -1
Two closed vessels of same volume are joined through a narrow tube and both vessels are filled with air of pressure 90 kPa and temperature 400 K. Keeping the temperature of one vessel constant at 400 K the second vessel temperature is raised to 500 K. The final pressure in the vessels is _______ kPa.
A
100
B
120
C
90
D
105
Official Correct Answer:Option (A)
Step-by-Step Solution:
Initial pressure, Pi=90 kPa
Initial temperature of vessel 1, T1=400 K
Initial temperature of vessel 2, T2=400 K
Final pressure, Pf=?
Final temperature of vessel 1, T1′=400 K
Final temperature of vessel 2, T2′=500 K
the total number of moles of air initially is equal to the total number of moles of air finally.
By the ideal gas law (PV=nRT), the number of moles n=RTPV.
Conservation of moles:
ninitial=nfinal
n1i+n2i=n1f+n2f
RT1PiV+RT2PiV=RT1′PfV+RT2′PfV
Pi(T11+T21)=Pf(T1′1+T2′1)
90(4001+4001)=Pf(4001+5001)
90(4002)=Pf(20005+4)
90(2001)=Pf(20009)
20090=Pf(20009)
Solve for Pf:
Pf=20090×92000
Pf=(990)×(2002000)
Pf=10×10
Pf=100 kPa
Q 11PhysicsSection A • MCQwave optics
+4 / -1
In interference experiment the path difference between two interfering waves at a point A on the screen is λ/3, where λ is the wavelength of these waves, and at another point B the path difference is λ/6. The ratio of intensities at points A and B is _______.
A
3
B
4
C
1/3
D
1/4
Official Correct Answer:Option (C)
Step-by-Step Solution:
ϕ=λ2π⋅Δx
I=4I0cos2(2ϕ)
ϕA=λ2π(3λ)=32π
IA=4I0cos2(22π/3)=4I0cos2(3π)
IA=4I0(21)2=4I0(41)=I0
ϕB=λ2π(6λ)=3π
IB=4I0cos2(2π/3)=4I0cos2(6π)
IB=4I0(23)2=4I0(43)=3I0
IBIA=3I0I0=31
Q 12PhysicsSection A • MCQsimple harmonic motion
+4 / -1
A particle is executing simple harmonic motion. Its amplitude is A and time period is 5 sec. The time required by it to move from x=A to x=2A is _______ sec.
A
1/4
B
5/4
C
5/8
D
3/8
Official Correct Answer:Option (C)
Step-by-Step Solution:
x(t)=Acos(ωt)
2A=Acos(ωt)
cos(ωt)=21
ωt=4π
T2πt=4π
t=8T
Given T=5: t=85
Q 13PhysicsSection A • MCQelectrostatics
+4 / -1
A thin half ring of radius 35 cm is uniformly charged with a total charge of Q coulomb. If the magnitude of the electric field at centre of the half ring is 100 V/m, then the value of Q is _______ nC. (ε0=8.85×10−12 C2/Nm2 and π=3.14)
A
2.14
B
2.44
C
3.25
D
0.7
Official Correct Answer:Option (A)
Step-by-Step Solution:
E=R2kλ
E=πR22kQ=2π2ε0R2Q
100=2×(3.14)2×(8.85×10−12)×(0.35)2Q
Q≈213.79×10−12 C
Q≈213.79×10−3 nC≈2.14 nC
Q 14PhysicsSection A • MCQsemiconductor devices and logic gates
+4 / -1
The maximum rated power of the LED is 2 mW and it is used in the circuit with input voltage of 5 V as shown in the figure below. The current through resistance RS is 0.5 mA. The minimum value of the resistance of RS, to ensure that the LED is not damaged is _______ kΩ.
A
6
B
2
C
4
D
5
Official Correct Answer:Option (B)
Step-by-Step Solution:
The Middle Diode: It points upwards against the 5 V downward current flow. It is reverse-biased (acts as an open circuit, carrying 0 mA).
The LED: It points downwards with the current flow. It is forward-biased and carries the entire current from RS.
Therefore, ILED=IS=0.5 mA
VLED=ILEDPLED=0.5 mA2 mW=4 V
Vin=VRS+VLED
5 V=(IS⋅RS)+4 V
1 V=0.5 mA×RS
RS=0.5×10−3 A1 V=2000Ω=2kΩ
Q 15PhysicsSection A • MCQelectromagnetic waves
+4 / -1
A point light source emits E.M. waves in free space. A detector, placed at a distance of L m, measures the intensity as I0. The detector is now shifted to another location on the same spherical surface ensuring the angle between original location and new location as 45∘. The measured intensity at new location will be _______.
A
4I0
B
I0
C
2I0
D
2I0
Official Correct Answer:Option (B)
Step-by-Step Solution:
I=4πr2P
The detector is moved to a new location on the same spherical surface. Therefore, the new distance from the source is still exactly L.
Since the distance L has not changed, the intensity remains exactly the same.
Q 16PhysicsSection A • MCQray optics
+4 / -1
A spherical interface lens of radius R separates two media of refractive indices 1 and 1.4 respectively as shown in the figure below. A point source is placed at a distance of 4R in front of spherical interface. The magnitude of the magnification of point source image is _______.
A
1.66
B
2.33
C
2.66
D
1.33
Official Correct Answer:Option (A)
Step-by-Step Solution:
vn2−un1=Rn2−n1
m=n2un1v
v1.4−−4R1=R1.4−1
v1.4+4R1=R0.4
v=0.61.4×4R=0.65.6R=328R
∣m∣=n2un1v
∣m∣=1.4×(−4R)1×(328R)
∣m∣=5.6R328R=3×5.628=16.828=35≈1.66
Q 17PhysicsSection A • MCQmoving charges and magnetism
+4 / -1
A small cube of side 1 mm is placed at the centre of a circular loop of radius 10 cm carrying a current of 2 A. The magnetic energy stored inside the cube is α×10−14 J. The value of α is _______. (μ0=4π×10−7 Tm/A, π=3.14)
A
6.28
B
6.28×10−6
C
628
D
6.28×10−4
Official Correct Answer:Option (A)
Step-by-Step Solution:
B=2Rμ0I
uB=2μ0B2
U=uB⋅V=2μ0B2⋅V
B=2×0.1(4π×10−7)×2=0.14π×10−7=4π×10−6 T
U=2×(4π×10−7)(4π×10−6)2×10−9
U=2×3.14×10−14=6.28×10−14 J
α=6.28
Q 18PhysicsSection A • MCQelectromagnetic induction
+4 / -1
An inductor of inductance 10 mH having resistance of 100 Ω is connected to battery of E.M.F. 1.0 V through a switch as shown in the figure below. After switch is closed, the ratio of instantaneous voltages across the inductor when the current passing through it is 2 mA and 4 mA is _______.
A
4/3
B
3/4
C
5/3
D
3/5
Official Correct Answer:Option (A)
Step-by-Step Solution:
Given parameters for the series RL circuit:
Inductance, L=10 mH
Resistance, R=100Ω
Battery E.M.F., E=1.0 V
According to Kirchhoff's Voltage Law (KVL)
E=VR+VL
Where:
VR is the voltage across the resistor (VR=iR)
VL is the instantaneous voltage across the inductor
Rearranging the equation to solve for VL:
VL=E−iR
VL1=E−i1R
VL1=1.0−(2×10−3)(100)
VL1=1.0−0.2
VL1=0.8 V
VL2=E−i2R
VL2=1.0−(4×10−3)(100)
VL2=1.0−0.4
VL2=0.6 V
Now, we calculate the ratio of these instantaneous voltages:
Ratio=VL2VL1
Ratio=0.6 V0.8 V
Ratio=68
Ratio=34
Q 19PhysicsSection A • MCQatoms and nuclei
+4 / -1
The ratio of momentum of the photons of the 1st and 2nd line of Balmer series of Hydrogen atoms is α/β. The possible values of α and β are:
A
27 and 20
B
3 and 16
C
5 and 36
D
20 and 27
Official Correct Answer:Option (D)
Step-by-Step Solution:
p=λh
From the Rydberg formula
λ1=R(nf21−ni21)
p∝(nf21−ni21)
For the Balmer series, the lower energy level is always nf=2.
For the 1st line of the Balmer series, the electron transitions from ni=3 to nf=2:
p1∝(221−321)
p1∝(41−91)
p1∝369−4
p1∝365
For the 2nd line of the Balmer series, the electron transitions from ni=4 to nf=2:
p2∝(221−421)
p2∝(41−161)
p2∝164−1
p2∝163
Now, we find the ratio of their momentums:
Ratio=p2p1
Ratio=3/165/36
Ratio=365×316
Ratio=9×35×4
Ratio=2720
Comparing this with the given ratio βα, the possible values are:
α=20
β=27
Q 20PhysicsSection A • MCQalternating current
+4 / -1
A LCR series circuit driven with Erms=90 V at frequency fd=30 Hz has resistance R=80Ω, an inductance with inductive reactance XL=20.0Ω and capacitance with capacitive reactance XC=80.0Ω. The power factor of the circuit is _______.
A
0.8
B
0.64
C
0.9
D
0.5
Official Correct Answer:Option (A)
Step-by-Step Solution:
The power factor of an alternating current circuit is defined as the cosine of the phase angle (ϕ) between the voltage and the current. It can be calculated using the ratio of the real resistance (R) to the total impedance (Z) of the circuit:
Power Factor=cosϕ=ZR
Z=R2+(XC−XL)2
Z=802+(80.0−20.0)2
Z=802+602
Z=10000
Z=100Ω
cosϕ=10080
cosϕ=0.8
Note that the given voltage (Erms) and frequency (fd) are not required to find the power factor since the reactances are already provided directly.
The power factor of the circuit is 0.8.
Q 21PhysicsSection B • Numericalcurrent electricity
+4 / -1
Refer to the circuit diagram given below. The heat generated across the 6 Ω resistance in 100 second is 100α J. The value of α is _______. (Nearest integer)
Answer Format:Enter numerical value rounded to the nearest integer
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
Req=R1+R2R1R2=6+46×4=1024=2.4Ω
Eeq=R11+R21R1E1+R2E2=61+4163+40=1250.5=50.5×12=1.2 V
Rtotal=3+Req=3+2.4=5.4Ω
Etotal=2 V−1.2 V=0.8 V
Itotal=RtotalEtotal=5.40.8=274 A
Vparallel=Eeq+ItotalReq
Vparallel=1.2+(274×2.4)=56+(274×512)=56+4516=4554+16=4570=914 V
I=6Vparallel−3=6914−3=6−913=−5413 A
H=I2Rt=(5413)2×6×100
H=2916169×600=2916101400≈34.77 J
100α=34.77⟹α≈3477
Q 22PhysicsSection B • Numericalwave optics
+4 / -1
An unpolarized light of intensity I0 passes through polarizer and then through a certain optically active solution and finally it goes to analyser. If the angle between analyser and polariser is 0∘ and intensity of light emerged from analyser is 83I0, the angle of rotation of the light by the solution with respect to analyser is _______ degrees.
Answer Format:Enter numerical value rounded to the nearest integer
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
When unpolarized light of intensity I0 passes through a polarizer, its intensity reduces to half: I1=2I0
If=I1cos2θ
83I0=(2I0)cos2θ
83=21cos2θ
θ=30∘
Q 23PhysicsSection B • Numericalatoms and nuclei
+4 / -1
The energy released when 17.137 kg of 37Li is converted into 24He by proton bombardment is α×1032 eV. The value of α is _______. (Nearest integer) (Mass of 37Li = 7.0183 u, mass of 24He = 4.004 u, mass of proton = 1.008 u and 1 u = 931 MeV/c2 and Avogadro number = 6.0×1023)
Answer Format:Enter numerical value rounded to the nearest integer
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
The nuclear reaction for the proton bombardment of Lithium-7 is:
37Li+11H→224He
Δm=m(37Li)+m(proton)−2×m(24He)
Δm=7.0183 u+1.008 u−2(4.004 u)
Δm=8.0263 u−8.0080 u
Δm=0.0183 u
The energy released per reaction (Q) is calculated using the given conversion factor 1 u=931 MeV/c2:
Q=0.0183×931 MeV
Q=17.0373 MeV
Q=17.0373×106 eV
Next, calculate the number of Lithium atoms (N) in the given sample mass.
The given mass is m=17.137 kg=17.137000 g
The molar mass of 37Li is approximately 7 g/mol.
Calculate the number of moles (n):
n=Molar MassMass=77000/17.13
n=17.131000 mol
Calculate the total number of atoms (N) using Avogadro's number (NA=6.0×1023):
N=n×NA
N=(17.131000)×6.0×1023
N=17.136.0×1026 atoms
The total energy released (E) is the total number of atoms multiplied by the energy released per reaction:
E=N×Q
E=(17.136.0×1026)×(17.0373×106 eV)
Rearranging the terms for simpler calculation:
E=6.0×(17.1317.0373)×1032 eV
Notice that the fraction is very close to 1 (17.1317.0373≈0.9946):
E≈6.0×0.9946×1032 eV
E≈5.967×1032 eV
Rounding to the nearest integer, we get:
E=6×1032 eV
Comparing this with the given format α×1032 eV, we find the value of α:
α=6
Q 24PhysicsSection B • Numericalelectrostatics
+4 / -1
A three coulomb charge moves from the point (0, -2, -5) to the point (5, 1, 2) in an electric field expressed as E=2xi^+3y2j^+4k^ N/C. The work done in moving the charge is _______ J.
Answer Format:Enter numerical value rounded to the nearest integer
Q 25PhysicsSection B • Numericalheat and thermodynamics
+4 / -1
A certain gas is isothermally compressed to (31)rd of its initial volume (V0=3 litre) by applying required pressure. If the bulk modulus of the gas is 3×105 N/m2, the magnitude of work done on the gas is _______ J.
Answer Format:Enter numerical value rounded to the nearest integer
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
B=P=3×105 N/m2
W=−nRTln(V0Vf)=−PV0ln(V0Vf)
Work Done=−PV0ln(V0Vf)
Work Done=−(3×105)×(3×10−3)×ln(31)
Work Done=−900×(−ln3)=900ln3
Magnitude of Work Done=900×1.098612≈988.75 J
Rounding off to the nearest integer gives 989 J.
Q 26ChemistrySection A • MCQsome basic concepts of chemistry
+4 / -1
An oxide of iron contains 69.9% iron, its empirical formula, is: (Given: Molar mass of Fe and O are 56 and 16 g mol−1 respectively.)
A
FeO
B
Fe2O3
C
Fe3O4
D
FeO3
Official Correct Answer:Option (B)
Step-by-Step Solution:
The oxide contains (69.9%) iron by mass. Therefore, the percentage of oxygen is
100−69.9=30.1
Assuming a (100\ \text{g}) sample,
Mass of Fe=69.9g,
Mass of O=30.1g.
The number of moles of each element is
Moles of Fe=5669.9≈1.248,
Moles of O=1630.1≈1.881.
Dividing both values by the smaller number of moles,
1.2481.248=1,
1.2481.881≈1.5.
Thus, the simplest ratio is
Fe:O=1:1.5.
Multiplying both terms by (2) to obtain whole numbers,
Fe:O=2:3.
Hence, the empirical formula of the oxide is
Fe2O3.
Therefore, the correct answer is (Fe_2O_3).
Q 27ChemistrySection A • MCQatomic structure
+4 / -1
If shortest wavelength of hydrogen atom in Lyman series is x, then longest wavelength in Balmer series of He− is:
A
59x
B
536x
C
4x
D
95x
Official Correct Answer:Option (A)
Step-by-Step Solution:
1. Core Formula
The Rydberg formula for the wavelength of light emitted during electronic transitions is:
1 / λ = R × Z² × [ (1 / n₁²) - (1 / n₂²) ]
Where:
λ = wavelength
R = Rydberg constant
Z = atomic number
n₁ = lower energy level
n₂ = higher energy level
2. Case 1: Shortest Wavelength of Hydrogen in Lyman Series
For the Hydrogen atom, the atomic number (Z) = 1.
For the Lyman series, the lower energy level (n₁) = 1.
The shortest wavelength corresponds to the maximum energy transition, which occurs when an electron drops from infinity (n₂ = ∞).
Given that this wavelength is x:
1 / x = R × 1² × [ (1 / 1²) - (1 / ∞) ]
1 / x = R × 1 × [ 1 - 0 ]
1 / x = R ⟶ Therefore, R = 1 / x
3. Case 2: Longest Wavelength of He⁺ in Balmer Series
For the Helium ion (He⁺), the atomic number (Z) = 2.
For the Balmer series, the lower energy level (n₁) = 2.
The longest wavelength corresponds to the minimum energy transition, which occurs from the very next shell (n₂ = 3).
Let's substitute these values into the formula:
1 / λ_He⁺ = R × 2² × [ (1 / 2²) - (1 / 3²) ]
1 / λ_He⁺ = 4R × [ (1 / 4) - (1 / 9) ]
1 / λ_He⁺ = 4R × [ (9 - 4) / 36 ]
1 / λ_He⁺ = 4R × [ 5 / 36 ]
1 / λ_He⁺ = 5R / 9
4. Substitute R = 1 / x
1 / λ_He⁺ = (5 / 9) × (1 / x)
1 / λ_He⁺ = 5 / 9x
Taking the reciprocal to solve for λ_He⁺:
λ_He⁺ = 9x / 5
Correct Answer:
9x / 5
Q 28ChemistrySection A • MCQatomic structure
+4 / -1
Match the LIST-I with LIST-II
List-I Orbital
List-II Radial nodes and nodal plane
A.
2s
I.
1 Radial node + two nodal planes
B.
3s
II.
1 Radial node + one nodal plane
C.
3p
III.
2 Radial nodes + No nodal plane
D.
4d
IV.
1 Radial node + No nodal plane
Choose the correct answer from the options given below:
A
A-IV, B-I, C-III, D-II
B
A-IV, B-II, C-III, D-I
C
A-III, B-I, C-IV, D-II
D
A-IV, B-III, C-II, D-I
Official Correct Answer:Option (D)
Step-by-Step Solution:
The number of angular (nodal) planes for an orbital is equal to the azimuthal quantum number (l), while the number of radial nodes is given by
Radial nodes=n−l−1.
For the (2s) orbital,
n=2,l=0,
so,
Angular nodes=0,
Radial nodes=2−0−1=1.
Hence,
A→IV.
For the (3s) orbital,
n=3,l=0,
so,
Angular nodes=0,
Radial nodes=3−0−1=2.
Hence,
B→III.
For the (3p) orbital,
n=3,l=1,
so,
Angular nodes=1,
Radial nodes=3−1−1=1.
Hence,
C→II.
For the (4d) orbital,
n=4,l=2,
so,
Angular nodes=2,
Radial nodes=4−2−1=1.
Hence,
D→I.
Therefore, the correct matching is
A→IV,B→III,C→II,D→I.
Hence, the correct answer is A-IV, B-III, C-II, D-I.
Q 29ChemistrySection A • MCQchemical bonding and molecular structure
+4 / -1
The pairs among A=[SO32−,CO32−], B=[O22−,F2], C=[CN−,CO], D=[NH3,H3O+] and E=[MnO42−,CrO42−] that do not have similar Lewis dot structure are:
A
A, B and E
B
A and E
C
B, C and D
D
C and D
Official Correct Answer:Option (B)
Step-by-Step Solution:
Species having the same number of atoms and the same total number of valence electrons are isoelectronic and generally possess similar Lewis dot structures.
For the pair ([SO_3^{2-},,CO_3^{2-}]),
SO32−:6+3(6)+2=26valence electrons,
CO32−:4+3(6)+2=24valence electrons.
Since the total number of valence electrons is different, their Lewis dot structures are not similar.
For the pair ([O_2^{2-},,F_2]),
O22−:2(6)+2=14valence electrons,
F2:2(7)=14valence electrons.
Both are isoelectronic and therefore have similar Lewis structures.
For the pair ([CN^-,,CO]),
CN−:4+5+1=10valence electrons,
CO:4+6=10valence electrons.
Both are isoelectronic and possess similar Lewis dot structures.
For the pair ([NH_3,,H_3O^+]),
NH3:5+3(1)=8valence electrons,
H3O+:6+3(1)−1=8valence electrons.
Both have the same electron count and similar trigonal pyramidal Lewis structures.
For the pair ([MnO_4^{2-},,CrO_4^{2-}]), although both contain tetrahedral oxyanions, the central atoms have different electronic configurations. In (MnO_4^{2-}), manganese is in the (+6) oxidation state with a (d^1) configuration, whereas in (CrO_4^{2-}), chromium is in the (+6) oxidation state with a (d^0) configuration. Hence, their Lewis dot structures are not considered similar.
Therefore, the pairs that do not have similar Lewis dot structures are A and E.
Hence, the correct answer is A and E.
Q 30ChemistrySection A • MCQthermodynamics
+4 / -1
Arrange the following isothermal processes in order of the magnitude of the work (p - V) involved between states 1 and 2.
A. Expansion in single stage wA B. Expansion in multi stages wB C. Compression in single stage wC D. Compression in multi stages wD
Choose the correct option.
A
∣wB∣>∣wA∣>∣wC∣>∣wD∣
B
∣wC∣>∣wD∣>∣wA∣>∣wB∣
C
∣wC∣>∣wD∣>∣wB∣>∣wA∣
D
∣wB∣>∣wA∣>∣wD∣>∣wC∣
Official Correct Answer:Option (C)
Step-by-Step Solution:
The magnitude of work done is equal to the area under the Pext−V curve.
For isothermal expansion:
A multistage expansion approaches a reversible process and gives maximum work.
A single-stage expansion is highly irreversible and gives less work.
Hence,
∣wB∣>∣wA∣
For isothermal compression:
A multistage compression approaches a reversible process and requires minimum work.
A single-stage compression is highly irreversible and requires maximum work.
Hence,
∣wC∣>∣wD∣
For the same initial and final states, the magnitude of reversible work lies between irreversible compression and irreversible expansion:
∣wC∣>∣wD∣>∣wrev∣>∣wB∣>∣wA∣
Since process D is closer to reversibility than process B,
∣wD∣>∣wB∣
Therefore, the overall order of the magnitude of work done is
∣wC∣>∣wD∣>∣wB∣>∣wA∣
Hence, the correct option is (C).
Q 31ChemistrySection A • MCQsolutions
+4 / -1
When 0.25 moles of a non-volatile, non-ionizable solute was dissolved in 1 mole of a solvent the vapor pressure of solution was x % of vapor pressure of pure solvent. What is x %?
A
50%
B
60%
C
70%
D
80%
Official Correct Answer:Option (D)
Step-by-Step Solution:
Given:
Moles of solute=0.25
Moles of solvent=1
For a non-volatile solute, according to Raoult’s law:
P∘P=Xsolvent
where,
P=vapour pressure of solution
P∘=vapour pressure of pure solvent
Mole fraction of solvent:
Xsolvent=total molesmoles of solvent
=1+0.251
=1.251=1.251
=0.8
Therefore,
P∘P=0.8
To convert into percentage:
x=0.8×100
=80%
Therefore, Option D 80%.
Q 32ChemistrySection A • MCQchemical equilibrium
+4 / -1
One mole each of He and A(g) are taken in a 10 L closed flask and heated to 400 K to establish the following equilibrium. A(g) ⇌ B(g) Kc for this reaction at 400 K is 4.0. The partial pressures (in atm) of He and B(g) are respectively (at equilibrium) (Assume He, A(g) and B(g) behave as ideal gases) (Given: R = 0.082 L atm K−1 mol−1)
A
3.28, 2.624
B
2.624, 3.28
C
3.28, 0.656
D
0.656, 6.56
Official Correct Answer:Option (A)
Step-by-Step Solution:
For the equilibrium
A(g)⇌B(g),
let (x) moles of (A) be converted into (B).
At equilibrium,
nA=1−x,nB=x,nHe=1.
Using the expression for the equilibrium constant,
Kc=[A][B]=(1−x)/Vx/V=1−xx=4.
Solving,
x=4(1−x),
x=4−4x,
5x=4,
x=0.8.
Therefore, the equilibrium amounts are
nA=0.2mol,nB=0.8mol,nHe=1.0mol.
Using the ideal gas equation,
P=VnRT,
with
R=0.082L atm K−1mol−1,T=400K,V=10L,
we obtain
VRT=100.082×400=3.28atm mol−1.
Hence, the partial pressure of helium is
PHe=1.0×3.28=3.28atm.
The partial pressure of (B(g)) is
PB=0.8×3.28=2.624atm.
Therefore, the equilibrium partial pressures are
PHe=3.28atm,PB=2.624atm,
which corresponds to Option A.
Q 33ChemistrySection A • MCQelectrochemistry
+4 / -1
Consider the following data.
Electrolyte
Λm∘ (S cm2 mol−1)
BaCl2
x1
H2SO4
x2
HCl
x3
BaSO4 is sparingly soluble in water. If the conductivity of the saturated BaSO4 solution is x S cm−1 then the solubility product of BaSO4 can be given as (Here Λm=Λm∘)
A
a2(x1+x2−2x3)2106x2
B
(x1+x2−2x3)2x2
C
106x2a2(x1+x2−2x3)2
D
(x1+x2+2x3)2x2
Official Correct Answer:Option (A)
Step-by-Step Solution:
According to Kohlrausch's Law, the limiting molar conductivity of an electrolyte is equal to the sum of the limiting ionic conductivities of its constituent ions.
where κ=xS cm−1 and (S) is the solubility in mol L−1.
Therefore,
S=Λm0(BaSO4)1000x,
S=x1+x2−2x31000x.
Since
BaSO4(s)⇌Ba2+(aq)+SO42−(aq),
the solubility product is
Ksp=[Ba2+][SO42−]=S2.
Substituting the value of (S),
Ksp=(x1+x2−2x31000x)2,
Ksp=(x1+x2−2x3)2106x2.
Hence, the correct expression for the solubility product is
Ksp=(x1+x2−2x3)2106x2.
Q 34ChemistrySection A • MCQp block elements
+4 / -1
Given below are two statements:
Statement I: Aluminium is more electropositive than thallium as the standard electrode potential value of EAl3+/Al∘ is negative and ETl3+/Tl∘ is positive.
Statement II: The sum of first three ionization enthalpies of boron is very high when compared to that of aluminium. Due to this reason boron forms covalent compounds only and aluminium forms Al3+ ion.
In the light of the above statements, choose the correct answer from the options given below:
A
Both Statement I and Statement II are true
B
Both Statement I and Statement II are false
C
Statement I is true but Statement II is false
D
Statement I is false but Statement II is true
Official Correct Answer:Option (A)
Step-by-Step Solution:
For Statement I:
Standard electrode potential of Aluminium:
EAl3+/Al∘=−1.66V
Standard electrode potential of Thallium:
ETl3+/Tl∘=+1.25V
More negative the reduction potential, greater is the tendency to lose electrons.
Hence, Aluminium loses electrons more easily than Thallium.
Therefore, Aluminium is more electropositive than Thallium.
Hence, Statement I is Correct.
For Statement II:
Boron has very high ionization enthalpy values.
Sum of first three ionization enthalpies of Boron is very high compared to Aluminium.
Therefore, removal of three electrons from Boron is difficult.
Hence, Boron does not form B3+ ions and mainly forms covalent compounds
Hence, Statement II is Correct.
Therefore, Option A is Correct
Q 35ChemistrySection A • MCQd and f block elements
+4 / -1
The correct statements among the following are.
A. Basic vanadium oxide is used in the manufacture of H2SO4. B. The spin-only magnetic moment value of the transition metal halide employed in Ziegler-Natta polymerization is 2.84 BM. C. The p-block metal compound employed in Ziegler-Natta polymerization has the metal in +3 oxidation state. D. The number of electrons present in the outer most 'd' orbital of metal halide employed in Wacker process is 8.
Choose the correct answer from the options given below:
A
A and B Only
B
A, C and D Only
C
C and D Only
D
B, C and D Only
Official Correct Answer:Option (C)
Step-by-Step Solution:
A. Basic vanadium oxide is used in the manufacture of H2SO4
In Contact Process, catalyst used is:V2O5
V2O5 is an acidic oxide, not a basic oxide.
Therefore, Statement A is Incorrect.
B. The transition metal halide employed in Ziegler-Natta polymerization has magnetic moment 2.84 BM.
Transition metal halide used in Ziegler-Natta catalyst:
TiCl4
Electronic configuration of Ti4+:
[Ar]3d0
Number of unpaired electrons:
n=0
Spin only magnetic moment:
μ=n(n+2)
=0(0+2)=0BM
Therefore, Statement B is Incorrect.
C.The p-block metal compound employed in Ziegler-Natta polymerization has metal in +3 oxidation state
The p-block metal compound used is:
Al(C2H5)3
Oxidation state of Aluminium: +3
Therefore, Statement C is Correct.
D. The number of electrons present in outermost d orbital of metal halide employed in Wacker process is 8D.
Metal halide used in Wacker process:
PdCl2
Oxidation state of Pd: +2
Electronic configuration of Pd:[Kr]4d105s0
Electronic configuration of Pd2+: [Kr]4d8
Therefore, number of electrons in outermost d orbital: =8
Hence, Statement D is Correct.
Therefore, Option C is Correct
Q 36ChemistrySection A • MCQcoordination compounds
+4 / -1
Match the LIST-I with LIST-II
List-I Electronic configuration of tetrahedral metal ion
List-II Crystal Field Stabilization Energy (Δt)
A.
d2
I.
-0.6
B.
d4
II.
-0.8
C.
d6
III.
-1.2
D.
d8
IV.
-0.4
Choose the correct answer from the options given below:
A
A-III, B-IV, C-II, D-I
B
A-III, B-I, C-IV, D-II
C
A-III, B-IV, C-I, D-II
D
A-II, B-I, C-IV, D-III
Official Correct Answer:Option (C)
Step-by-Step Solution:
For tetrahedral complexes, the (e) orbitals are stabilized by (0.6\Delta_t) and the (t_2) orbitals are destabilized by (0.4\Delta_t). Therefore, the Crystal Field Stabilization Energy (CFSE) is given by
CFSE=[n(e)(−0.6)+n(t2)(+0.4)]Δt.
For a (d^2) configuration, the electron distribution is (e^2t_2^0). Hence,
CFSE=2(−0.6)Δt+0(+0.4)Δt=−1.2Δt,
which corresponds to III.
For a (d^4) configuration, the electron distribution is (e^2t_2^2). Thus,
Hence, the correct sequence is A-III, B-IV, C-I, D-II.
Q 37ChemistrySection A • MCQcoordination compounds
+4 / -1
Which of the following are true about the energy of the given d-orbitals of a tetrahedral complex?
A. dxy=dxz>dx2−y2 B. dxy=dyz>dz2 C. dx2−y2>dz2>dxz D. dx2−y2=dz2<dxz
Choose the correct answer from the given below:
A
A, B and D only
B
A and B only
C
B and D only
D
B, C and D only
Official Correct Answer:Option (A)
Step-by-Step Solution:
For a tetrahedral complex, the five degenerate d-orbitals split into two distinct energy levels due to electrostatic repulsion from the ligands:
Lower Energy Set (e orbitals): Consists of dx2−y2 and dz2. These point between the axes where ligand approach causes less repulsion.
Higher Energy Set (t2 orbitals): Consists of dxy, dyz, and dxz. These point directly toward the directions from which the ligands approach, experiencing more repulsion.
Therefore, the relative energies are:
dxy=dyz=dxz>dx2−y2=dz2
Evaluating the Statements:
A. dxy=dxz>dx2−y2 True (Both dxy and dxz belong to the higher-energy t2 set, while dx2−y2 belongs to the lower-energy e set).
B. dxy=dyz>dz2 True (Both dxy and dyz are in the higher t2 set, and dz2 is in the lower e set).
C. dx2−y2>dz2>dxz False (dx2−y2 and dz2 have equal energy).
D. dx2−y2=dz2<dxzTrue (dx2−y2 and dz2 are equal and lower in energy than the t2 orbital dxz).
Correct Answer:
A, B and D only
Q 38ChemistrySection A • MCQbasics of organic chemistry
+4 / -1
Rf value for 2-methylpropene in a solvent system (Ethyl acetate + ether) is 0.42. 2-methylpropene is treated with dilute H2SO4 to give major organic product (X). Rf value for (X) in the same solvent system under identical condition will be:
A
0.42
B
0.82
C
0.62
D
0.12
Official Correct Answer:Option (D)
Step-by-Step Solution:
Reaction of 2-methylpropene with dilute sulphuric acid gives alcohol by hydration.
Reaction:
CH2=C(CH3)2+H2O+dil.H2SO4⟶(CH3)COH
Major Product Formed:
X= tert-butyl alcohol(2-methylpropan-2-ol)
In TLC:
Rf=Distance travelled by solventDistance travelled by compound
More polar compounds interact more strongly with polar stationary phase and therefore move less.
Hence:
More polar compound =>Lower Rf value
2-methylpropene is non-polar.
tert-butyl alcohol contains: −OH group and is more polar.
Therefore, product X will have lower Rf value than 0.42.
Hence,
Rf value of X<0.42
Therefore, Option D is correct
Q 39ChemistrySection A • MCQbasics of organic chemistry
+4 / -1
Given below are two statements:
Statement I: 2,6-diethylcyclohexanone and 6-methyl-2-n-propylcyclohexanone are metamers.
In the light of the above statements, choose the correct answer from the options given below:
A
Both Statement I and Statement II are true
B
Both Statement I and Statement II are false
C
Statement I is true but Statement II is false
D
Statement I is false but Statement II is true
Official Correct Answer:Option (C)
Step-by-Step Solution:
Metamerism arises due to the different distribution of alkyl groups on either side of the same polyvalent functional group while retaining the same molecular formula.
In 2,6-diethylcyclohexanone, the carbonyl group is associated with two ethyl substituents, whereas in 6-methyl-2-(n)-propylcyclohexanone, it is associated with a methyl group and an (n)-propyl group. Both compounds have the same molecular formula but differ in the distribution of alkyl groups around the carbonyl functionality. Hence, they are metamers.
Therefore, Statement I is true.
Keto-enol tautomerism requires the presence of at least one (\alpha)-hydrogen atom adjacent to the carbonyl group.
In 2,2,6,6-tetramethylcyclohexanone, both (\alpha)-carbon atoms are fully substituted by two methyl groups each and do not possess any (\alpha)-hydrogen atoms. Consequently, the compound cannot undergo keto-enol tautomerism.
Therefore, Statement II is false.
Hence, Statement I is true, Statement II is false, and the correct answer is Option C.
Q 40ChemistrySection A • MCQhydrocarbons
+4 / -1
Given below are two statements:
Statement I: Methane can be prepared by decarboxylation of sodium ethanoate, Kolbe's electrolysis of sodium acetate and reaction of CH3MgBr with water. Statement II: Methane cannot be prepared from unsaturated hydrocarbons and by Wurtz reaction.
In the light of the above statements, choose the correct answer from the options given below:
A
Both Statement I and Statement II are true
B
Both Statement I and Statement II are false
C
Statement I is true but Statement II is false
D
Statement I is false but Statement II is true
Official Correct Answer:Option (D)
Step-by-Step Solution:
In Statement I, methane can be prepared by decarboxylation of sodium ethanoate with soda lime:
CH3COONa+NaOHΔ,CaOCH4+Na2CO3.
Methane is also obtained by the hydrolysis of methyl magnesium bromide:
CH3MgBr+H2O→CH4+Mg(OH)Br.
However, Kolbe's electrolysis of sodium acetate does not produce methane. Instead, it gives ethane by coupling of methyl radicals:
2CH3COO−electrolysisC2H6+2CO2.
Therefore, Statement I is false.
In Statement II, methane cannot be prepared by hydrogenation of unsaturated hydrocarbons because hydrogenation only converts alkenes or alkynes into higher alkanes and cannot reduce the carbon count to one. Methane also cannot be prepared by the Wurtz reaction since Wurtz coupling always combines two alkyl halides to form a higher alkane containing at least two carbon atoms.
Therefore, Statement II is true.
Hence, Statement I is false, Statement II is true, and the correct answer is Option D.
Q 41ChemistrySection A • MCQhydrocarbons
+4 / -1
Given below are two statements:
Statement I: 3-phenylpropene reacts with HBr and gives secondary alkyl bromide having a chiral carbon atom as the major product.
Statement II: Aryl chlorides and aryl cyanides can be prepared by Sandmeyer reaction as well as Gattermann reaction.
In the light of the above statements, choose the correct answer from the options given below:
A
Both Statement I and Statement II are true
B
Both Statement I and Statement II are false
C
Statement I is true but Statement II is false
D
Statement I is false but Statement II is true
Official Correct Answer:Option (C)
Step-by-Step Solution:
For Statement I, 3-phenylpropene ((C_6H_5CH_2CH=CH_2)) undergoes electrophilic addition with (HBr) according to Markovnikov’s rule. Protonation of the double bond generates a resonance-stabilized benzylic carbocation, which is then attacked by (Br^-) to form 1-phenyl-1-bromopropane.
The product formed is
C6H5CH(Br)CH2CH3.
The carbon bearing the bromine atom is attached to four different groups ((Br,\ H,\ CH_2CH_3,\ C_6H_5)), making it a chiral carbon. Hence, Statement I is true.
For Statement II, the Sandmeyer reaction is used to prepare aryl chlorides and aryl cyanides from diazonium salts using cuprous salts. Although the Gattermann reaction can be employed for the preparation of aryl chlorides and aryl bromides, it is not the standard method for the preparation of aryl cyanides.
Therefore, Statement II is false.
Hence, Statement I is true, Statement II is false, and the correct answer is Option C.
Q 42ChemistrySection A • MCQalcohols phenols and ethers
+4 / -1
Consider the following sequence of reactions
The major product P is:
A
B
C
D
Official Correct Answer:Option (C)
Step-by-Step Solution:
tert-butyl alcohol is a tertiary (3∘) alcohol. When heated with copper at 573K, tertiary alcohols cannot undergo dehydrogenation because they do not possess an α-hydrogen. Instead, they undergo dehydration to form an alkene.
(CH3)3COHCu/573,K(CH3)2C=CH2+H2O
Thus, the intermediate formed is 2-methylpropene.
In the next step, 2-methylpropene reacts with benzoic acid in the presence of an acid catalyst.
The alkene is first protonated to give the most stable carbocation:
(CH3)2C=CH2+H+→(CH3)3C+
The oxygen atom of benzoic acid then attacks the tert-butyl carbocation, followed by deprotonation to form an ester:
PhCOOH+(CH3)3C+→PhCOOC(CH3)3+H+
Hence, the final product P is tert-butyl benzoate,
PhCOOC(CH3)3
Therefore, the correct option is (C).
Q 43ChemistrySection A • MCQalcohols phenols and ethers
+4 / -1
Arrange the following compounds according to increasing order of boiling points. n-C4H9OH (A), n-C4H9NH2 (B), n-C4H10 (C) and C2H5NHC2H5 (D).
A
C < B < A < D
B
D < C < B < A
C
C < D < B < A
D
D < B < A < C
Official Correct Answer:Option (C)
Step-by-Step Solution:
The boiling point of a compound depends primarily on the strength of its intermolecular forces. Stronger intermolecular attractions require more energy to overcome, resulting in a higher boiling point.
(n)-Butane ((C)) is a non-polar hydrocarbon and exhibits only London dispersion forces. Therefore, it has the lowest boiling point among the given compounds.
Diethylamine ((D)) is a secondary amine and possesses an (N-H) bond, allowing intermolecular hydrogen bonding. However, the extent of hydrogen bonding is less than that in a primary amine.
(n)-Butylamine ((B)) is a primary amine and forms stronger and more extensive intermolecular hydrogen bonding than diethylamine, giving it a higher boiling point.
(n)-Butanol ((A)) contains an (O-H) bond, and oxygen is more electronegative than nitrogen. Consequently, alcohols exhibit stronger hydrogen bonding than amines, making butanol the highest boiling compound in the given set.
Therefore, the increasing order of boiling points is
C<D<B<A.
Hence, the correct answer is C < D < B < A.
Q 44ChemistrySection A • MCQbiomolecules
+4 / -1
Match the LIST-I with LIST-II
List-I Deficiency Disease
List-II Vitamin
A.
Scurvy
I.
Pyridoxine
B.
Convulsions
II.
Vitamin A
C.
Cheilosis
III.
Ascorbic Acid
D.
Xerophthalmia
IV.
Riboflavin
Choose the correct answer from the options given below:
A
A-I, B-III, C-II, D-IV
B
A-I, B-III, C-IV, D-II
C
A-III, B-I, C-IV, D-II
D
A-III, B-I, C-II, D-IV
Official Correct Answer:Option (C)
Step-by-Step Solution:
Scurvy is caused by a deficiency of ascorbic acid (Vitamin C). It is characterized by symptoms such as bleeding gums and delayed wound healing. Therefore,
A→III.
Convulsions may occur due to a deficiency of pyridoxine (Vitamin (B_6)). Hence,
B→I.
Cheilosis, which is characterized by cracks and fissures at the corners of the mouth, is caused by a deficiency of riboflavin (Vitamin (B_2)). Therefore,
C→IV.
Xerophthalmia is an eye disorder caused by a deficiency of Vitamin A and is characterized by dryness of the conjunctiva and cornea. Hence,
D→II.
Thus, the correct matching is
A→III,B→I,C→IV,D→II.
Therefore, the correct answer is A-III, B-I, C-IV, D-II.
Q 45ChemistrySection A • MCQbiomolecules
+4 / -1
Match the LIST-I with LIST-II
List-I Amino acid
List-II Positive reaction/Test for functional group present in side chain of amino acid
A.
Glutamine
I.
Hinsberg's test
B.
Lysine
II.
Neutral FeCl3 test
C.
Tyrosine
III.
Ceric ammonium nitrate test
D.
Serine
IV.
Hoffman bromamide degradation
Choose the correct answer from the options given below:
A
A-IV, B-II, C-I, D-III
B
A-IV, B-I, C-II, D-III
C
A-III, B-II, C-I, D-IV
D
A-IV, B-I, C-III, D-II
Official Correct Answer:Option (B)
Step-by-Step Solution:
A. Glutamine \longrightarrow\ IV.
Hoffmann bromamide degradation: Glutamine have an aliphatic primary amide group CONH2 in its side chain. Primary amides undergoes the Hoffmann bromamide reaction when treated with Br2 and an alkali so that it can degrade into an amine.
B. Lysine \longrightarrow\ I.
Hinsberg's test: Lysine contains a primary aliphatic amino group NH2 at the terminal end epsilon−Position of its side chain. The Hinsberg's Test (using benzene sulfonyl chloride) is a test used to identify and differentiate primary amines.
C. Tyrosine \longrightarrow\ II.
Neutral FeCl3 test: Tyrosine contains a phenolic group OH attached to a benzene ring in its side chain. Phenols react characteristically with neutral ferric chlorideFeCl3 to form highly colored coordination complexes (typically violet/purple).
D. Serine \longrightarrow\ III.
Ceric ammonium nitrate (CAN) test: Serine have an aliphatic primary alcohol group CH2OH in its side chain. The Ceric Ammonium Nitrate (CAN) test is a standard functional group test used to confirm the presence of aliphatic alcohols (producing a red/pink complex).
Q 46ChemistrySection B • Numericalperiodic classification of elements
+4 / -1
First and second ionization enthalpies of lithium are 520 kJ mol−1 and 7297 kJ mol−1 respectively. Energy required to convert 3.5 mg lithium (g) into Li2+(g) [Li(g) → Li2+(g)] is _______ kJ mol−1. (nearest integer) [Molar mass of Li = 7 g mol−1]
Answer Format:Enter numerical value rounded to the nearest integer
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
Given:
IE1ofLi=520kJmol−1
IE2ofLi=7297kJmol−1
Reaction:
Li(g)⟶Li+2(g)+2e−
Total energy required for one mole:
=IE1+IE2
=520+7297
=7817kJmol−1
Given Mass of Li: 3.5×10−3g
Moles of Li :
=73.5×10−3g
=5×10−4mol
Therefore energy required is:
=7817×5×10−4
=3.9085kJ
Nearest Integer is 4.
Q 47ChemistrySection B • Numericalcompounds containing nitrogen
+4 / -1
Consider the following sequence of reactions.
The percentage of nitrogen in the yellow product (X) formed is _______ %. (Nearest Integer) (Given Molar mass in g mol−1 H:1, C:12, N:14)
Answer Format:Enter numerical value rounded to the nearest integer
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
When diazoaminobenzene is warmed to 40-45∘C in the presence of hydrochloric acid (HCl) and excess aniline, it rearranges to form p-aminoazobenzene (a well-known yellow dye).
The product formed from the reaction
Structure of p-aminoazobenzene:C6H5−N=N−C6H4−NH2
Molecular Formula:C12H11N3
Using the provided atomic masses (' in math mode at position 14: \text{C} = 12̲, \text{H} = 1…" style="color:#cc0000">\text{C} = 12, H=1, $\text{N} = 14):
Molar Mass=(12×12)+(11×1)+(3×14) Molar Mass=144+11+42=197 g mol−1
The total mass contributed by the 3 nitrogen atoms in one mole of the compound is:
Mass of Nitrogen=3×14=42 g mol−1
Now, find the mass percentage:
Percentage of Nitrogen=(19742)×100≈21.32%
Rounding to the nearest integer gives 21%.
Q 48ChemistrySection B • Numericalalcohols phenols and ethers
+4 / -1
4.7 g of phenol is heated with Zn to give product X. If this reaction goes to 60% completion then the number of moles of compound X formed will be _______ ×10−2. (Nearest Integer) (Given molar mass in g mol−1: H:1, C:12, O:16)
Answer Format:Enter numerical value rounded to the nearest integer
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
1. Identify the Reaction
When phenol is heated with zinc (Zn) dust, it undergoes a reduction reaction to form benzene (product X) and zinc oxide.
Reaction equation:
Phenol + Zn -> Benzene + ZnO
From the balanced equation, 1 mole of phenol produces 1 mole of benzene.
2. Calculate the Molar Mass of Phenol
Formula of Phenol: C6H6O (or C6H5OH)
Carbon (C): 6 atoms * 12 = 72
Hydrogen (H): 6 atoms * 1 = 6
Oxygen (O): 1 atom * 16 = 16
Total Molar Mass of Phenol = 72 + 6 + 16 = 94 grams/mole
3. Calculate the Initial Moles of Phenol
Given mass of phenol = 4.7 grams
Initial moles of phenol = Given mass / Molar mass
Initial moles of phenol = 4.7 / 94 = 0.05 moles
4. Calculate the Moles of Benzene (Product X) Formed
Since the reaction only goes to 60% completion:
Moles of product X = Initial moles of phenol * 60%
Moles of product X = 0.05 * (60 / 100)
Moles of product X = 0.03 moles
5. Convert to the Required Scientific Format
The question asks for the answer in the form: ______ * 10^-2
0.03 can be written as 3 * 10^-2
Final Answer
3
Q 49ChemistrySection B • Numericalchemical kinetics
+4 / -1
Sucrose hydrolyses in acidic medium into glucose and fructose by first order rate law with t1/2=3 hour. The percentage of sucrose remaining after 6 hours is _______. (Nearest integer) (Given: log 2 = 0.3010 and log 3 = 0.4771)
Answer Format:Enter numerical value rounded to the nearest integer
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
For a first-order reaction, the half-life remains constant.
The number of half-lives elapsed in 6hours is
n=t1/2t=36=2
After the first half-life:
100
After the second half-life:
50
Alternatively,
Amount remaining=2nInitial amount=22100=25
Therefore, the percentage of sucrose remaining after 6hours is
25
Hence, the correct answer is 25.
Q 50ChemistrySection B • Numericalthermodynamics
+4 / -1
Consider the reaction X ⇌ Y at 300 K. If ΔHθ and K are 28.40 kJ mol−1 and 1.8×10−7 at the same temperature, then the magnitude of ΔSθ for the reaction in J K−1 mol−1 is _______. (Nearest integer) (Given: R = 8.3 J K−1 mol−1, ln 10 = 2.3, log 3 = 0.48, log 2 = 0.30)
Answer Format:Enter numerical value rounded to the nearest integer
Step 2: Calculate the Standard Gibbs Free Energy Change △G∘
The relation between Gibbs free energy and the equilibrium constant is given by:
△G∘=RTlnK
Using the relation lnK=ln10×log10K:
log10K=log10(1.8×10−7)=log10(1.8)−7
We can express log10(1.8) using given values:
log10(1.8)=log10(1018)=log10(2×32)−log10(10)
log10(1.8)=log102+2log103−1
log10(1.8)=0.30+2(0.48)−1=0.30+0.96−1=0.26
Now, substitute this back to find log10K:
log10K=0.26−7=−6.74
Next, convert to natural logarithm:
lnK=2.3×(−6.74)=−15.502
Now, solve for △G∘:
△G∘=−(8.3JK−1mol−1)×(−15.502)=+38600Jmol−1
Step 3: Calculate the Standard Entropy Change △S∘
Using thermodynamic relation:
△G∘=△H∘−T△S∘
T△S∘=△H∘−△G∘
300\times\ \triangle\ S^{\circ\ }=28400-38600\
300\times\ \triangle\ S^{\circ\ }=-10200\
△S∘=−30010200=−34JK−1mol−1
Therefore, the magnitude of ∣△S∘∣=34
Therefore, the correct is 34.
Q 51MathematicsSection A • MCQfunctions
+4 / -1
Let [⋅] denote the greatest integer function. If the domain of the function f(x)=sin−1(3x+[x]) is [α,β), then α2+β2 is equal to:
A
2
B
5
C
10
D
13
Official Correct Answer:Option (B)
Step-by-Step Solution:
−1≤3x+⌊x⌋≤1
⇒−3≤x+⌊x⌋≤3
⇒−3−⌊x⌋≤x≤3−⌊x⌋
If ⌊x⌋=−1⇒x∈[−1,0)
If ⌊x⌋=0⇒x∈[0,1)
If ⌊x⌋=1⇒x∈[1,2)
Hence x∈[−1,2)
⇒α=−1 and β=2
⇒α2+β2=(−1)2+22=5
Q 52MathematicsSection A • MCQquadratic equations
+4 / -1
Let one root of the quadratic equation in x: (k2−15k+27)x2+9(k−1)x+18=0 be twice the other. Then the length of the latus rectum of the parabola y2=6kx is equal to:
A
4
B
6
C
8
D
12
Official Correct Answer:Option (D)
Step-by-Step Solution:
(k2−15k+27)x2+9(k−1)x+18=0
Let the roots be α and 2α
Sum of roots: 3α=k2−15k+27−9(k−1)⟹α=k2−15k+27−3(k−1)— (Equation 1)
Product of roots: 2α2=k2−15k+2718⟹α2=k2−15k+279— (Equation 2)
(k2−15k+27−3(k−1))2=k2−15k+279
(k2−15k+27)29(k−1)2=k2−15k+279
Since k2−15k+27=0 for a valid quadratic equation, we can cancel out common terms from both sides:
(k−1)2=k2−15k+27
k2−2k+1=k2−15k+27
13k=26⟹k=2
Length of Latus Rectum=6k=6(2)=12
Q 53MathematicsSection A • MCQhyperbola
+4 / -1
Let e1 and e2 be two distinct roots of the equation x2−ax+2=0. Let the sets {a∈R:e1,e2 are the eccentricities of hyperbolas}=(α,β), and {a∈R:e1,e2 are the eccentricities of an ellipse and a hyperbola, respectively}=(γ,∞). Then α2+β2+γ2 is equal to:
A
18
B
22
C
26
D
34
Official Correct Answer:Option (C)
Step-by-Step Solution:
Sum of roots: e1+e2=a and Product of roots: e1e2=2
For distinct real roots, the discriminant D>0:
a2−8>0⟹a>22
1. Both roots are Hyperbola eccentricities:
For a quadratic function f(x)=x2−ax+2 to have both roots greater than 1:
Discriminant: D>0⟹a>22
Vertex position: −2ab>1⟹2a>1⟹a>2
Boundary condition: f(1)>0⟹12−a(1)+2>0⟹a<3
Intersecting all three conditions: a∈(22,3)
α=22,β=3
2. One ellipse and one hyperbola eccentricity:
For an ellipse, 0<e1<1, and for a hyperbola, e2>1.
Since the product of the roots is e1e2=2, choosing 0<e1<1 automatically ensures that e2=e12>2, satisfying the hyperbola condition (e2>1).
For f(x)=x2−ax+2 to have exactly one root between 0 and 1 and the other root greater than 1, the value of the function at the boundary x=1 must be negative: f(1)<0⟹1−a+2<0⟹a>3
γ=3
α2+β2+γ2=8+9+9=26
Q 54MathematicsSection A • MCQcomplex numbers
+4 / -1
Let the set of all values of k∈R such that the equation z(zˉ+2+i)+k(2+3i)=0, z∈C, has at least one solution, be the interval [α,β]. Then 9(α+β) is equal to:
Q 56MathematicsSection A • MCQsequences and series
+4 / -1
The sum of the first ten terms of an A.P. is 160 and the sum of the first two terms of a G.P. is 8. If the first term of the A.P. is equal to the common ratio of the G.P. and the first term of the G.P. is equal to common difference of the A.P., then the sum of all possible values of the first term of the G.P. is:
A
934
B
1334
C
932
D
1332
Official Correct Answer:Option (A)
Step-by-Step Solution:
Sum of first n terms of an AP: Sn=2n[2a+(n−1)d]
Sum of first 2 terms of a GP: S2=A+Ar
S10=210[2a+9d]=160
5[2r+9A]=160
2r+9A=32⟹r=232−9A
A+Ar=8⟹A(1+r)=8
A(1+232−9A)=8
9A2−34A+16=0
Sum of values of A=934
Q 57MathematicsSection A • MCQpermutations and combinations
+4 / -1
The number of 4-letter words, with or without meaning, each consisting of two vowels and two consonants that can be formed from the letters of the word INCONSEQUENTIAL, without repeating any letter, is:
A
2670
B
2840
C
2920
D
3600
Official Correct Answer:Option (D)
Step-by-Step Solution:
Vowels: I (2), O (1), E (1), U (1), A (1) ⟹ Number of distinct vowels = 5 ({I, O, E, U, A})
Consonants: N (3), C (2), S (1), Q (1), T (1), L (1) ⟹ Number of distinct consonants = 6 ({N, C, S, Q, T, L})
Ways to choose 2 distinct vowels from 5:5C2=2×15×4=10 Ways to choose 2 distinct consonants from 6:6C2=2×16×5=15 The selected 4 letters can be arranged among themselves in 4! ways. Total Words=5C2×6C2×4! Total Words=10×15×24=150×24=3600
Q 58MathematicsSection A • MCQbinomial theorem
+4 / -1
If the coefficients of the middle terms in the binomial expansions of (1+αx)26 and (1−αx)28, α=0, are equal, then the value of α is:
A
1
B
1314
C
727
D
277
Official Correct Answer:Option (D)
Step-by-Step Solution:
For (1+αx)26, the middle term index is r=226=13.
The middle term is T14=(1326)(αx)13
C1=(1326)α13
Similarly, C2=(1428)α14
(1326)α13=(1428)α14
α=(1428)(1326)
α=14!14!28!13!13!26!
α=28!26!×13!×13!14!×14!
α=28×271×(14×14)=277
Q 59MathematicsSection A • MCQstatistics
+4 / -1
A data consists of 20 observations x1,x2,...,x20. If ∑i=120(xi+5)2=2500 and ∑i=120(xi−5)2=100, then the ratio of mean to standard deviation of this data is:
Add Equation 1 and Equation 2: 2∑xi2=2000−400=1600 ∑xi2=800
σ2=n∑xi2−(xˉ)2 σ2=20800−(6)2=40−36=4 σ=4=2
Ratio =σxˉ=26=3
Q 60MathematicsSection A • MCQprobability
+4 / -1
A bag contains (N + 1) coins - N fair coins, and one coin with 'Head' on both sides. A coin is selected at random and tossed. If the probability of getting 'Head' is 169, then N is equal to:
A
5
B
7
C
8
D
9
Official Correct Answer:Option (B)
Step-by-Step Solution:
P(H)=P(F)⋅P(H∣F)+P(B)⋅P(H∣B)
Probability of choosing a fair coin: P(F)=N+1N
Probability of choosing the two-headed coin: P(B)=N+11
P(H∣F)=21
P(H∣B)=1
Given that P(H)=169:
169=(N+1N×21)+(N+11×1)
169=2(N+1)N+N+11
169=2(N+1)N+2
2N=14⟹N=7
Q 61MathematicsSection A • MCQhyperbola
+4 / -1
If the eccentricity e of the hyperbola a2x2−b2y2=1, passing through (6,43), satisfies 15(e2+1)=34e, then the length of the latus rectum of the hyperbola b2x2−2(a2+1)y2=1 is:
A
10
B
20
C
25
D
30
Official Correct Answer:Option (A)
Step-by-Step Solution:
15(e2+1)=34e⟹15e2−34e+15=0
⟹(5e−3)(3e−5)=0
e=35 (e>1)
b2=a2(925−1)⟹b2=916a2— (1)
The hyperbola passes through the point (6,43):
a262−b2(43)2=1⟹a236−b248=1
a236−(916a2)48=1
a236−16a248×9=1⟹a236−a227=1⟹a29=1
∴a2=9
b2=916(9)=16
b2x2−2(a2+1)y2=1
Comparing this with the standard form A2x2−B2y2=1:
A2=b2=16
B2=2(a2+1)=2(9+1)=20
The formula for the length of the latus rectum is: Length=A2B2=162(20)=440=10
Q 62MathematicsSection A • MCQparabola
+4 / -1
Let chord PQ of length 313 of the parabola y2=12x be such that the ordinates of points P and Q are in the ratio 1:2. If the chord PQ subtends an angle α at the focus of the parabola, then sinα is equal to:
A
53
B
54
C
135
D
1312
Official Correct Answer:Option (A)
Step-by-Step Solution:
4a=12⟹a=3
P=(3t12,6t1)andQ=(3t22,6t2)
6t26t1=21⟹t2=2t1
Q=(3(2t1)2,6(2t1))=(12t12,12t1)
PQ2=(12t12−3t12)2+(12t1−6t1)2
(313)2=(9t12)2+(6t1)2
(9t12+13)(t12−1)=0
t12=1⟹t1=1(taking positive parameter for simplicity)
Thus, our parameters are t1=1 and t2=2
Using the property F(x1,y1)=a(1+t2):
FP=3(1+t12)=3(1+1)=6
FQ=3(1+t22)=3(1+22)=15
cosα=2⋅FP⋅FQFP2+FQ2−PQ2 (Cosine rule)
cosα=2⋅6⋅1562+152−(313)2
cosα=18036+255−117=180144=54
sinα=1−(54)2=53
Q 63MathematicsSection A • MCQinverse trigonometric functions
+4 / -1
Let 0<α<1, β=3α1 and tan−1(1−α)+tan−1(1−β)=4π. Then 6(α+β) is equal to:
A
6
B
7
C
8
D
9
Official Correct Answer:Option (B)
Step-by-Step Solution:
tan−1x+tan−1y=tan−1(1−xyx+y)(for xy<1)
tan−1(1−α)+tan−1(1−β)=4π
1−(1−α)(1−β)(1−α)+(1−β)=tan(4π)
1−(1−α−β+αβ)2−α−β=1
α+β−αβ2−α−β=1
2−α−β=α+β−αβ
2−2(α+β)+αβ=0— (Equation 1)
β=3α1⟹αβ=31
2−2(α+β)+31=0
37=2(α+β)
6(α+β)=3×[2(α+β)]
6(α+β)=3×37=7
Q 64MathematicsSection A • MCQtrigonometric equations
+4 / -1
Let S={θ∈(−2π,2π):cosθ+1=3sinθ}. Then the ∑θ∈Sθ is equal to:
A
32π
B
34π
C
−32π
D
−34π
Official Correct Answer:Option (D)
Step-by-Step Solution:
cosθ−3sinθ=−1
Divide the equation by 12+(−3)2=1+3=2:
21cosθ−23sinθ=−21
cos(3π)cosθ−sin(3π)sinθ=−21
cos(θ+3π)=−21
θ+3π=2nπ±32π
θ=2nπ+3π or θ=2nπ−π
The set of solutions is S={−35π,−π,3π,π}.
∑θ∈Sθ=−35π−π+3π+π
∑θ∈Sθ=−34π
Q 65MathematicsSection A • MCQ3d geometry
+4 / -1
Let the image of the point P(1, 6, a) in the line L: 1x=2y−1=bz−a+1, b>0, be (3a,0,a+c). If S(α,β,γ), α>0, is the point on L such that the distance of S from the foot of perpendicular from the point P on L is 214, then α+β+γ is equal to:
A
19
B
20
C
21
D
22
Official Correct Answer:Option (C)
Step-by-Step Solution:
L:1x=2y−1=bz−a+1
The foot of the perpendicular M is the midpoint of the segment joining point P(1,6,a) and its image Q(3a,0,a+c):
M=(21+3a,26+0,2a+a+c)=(63+a,3,22a+c)
Since M lies on line L, substituting y=3 into the line equation gives: 1x=23−1=1⟹x=1
63+a=1⟹a=3
P=(1,6,3) and M=(1,3,26+c)
bz−a+1=1⟹b(26+c)−3+1=1⟹2c=b⟹c=2b
PM=M−P=(1−1,3−6,1+b−3)=(0,−3,b−2)
The direction vector of line L is d=(1,2,b). Since vector PM is perpendicular to line L: PM⋅d=0⟹(0)(1)+(−3)(2)+(b−2)(b)=0
−6+b2−2b=0⟹b2−2b−6=0— (1)
Let any general point S(α,β,γ) on line L be expressed in terms of parameter t: S=(t,2t+1,bt+2)
SM2=(214)2=56
(t−1)2+(2t+1−3)2+(bt+2−(1+b))2=56
5(t−1)2+(b(t−1)+1)2=56
Let k=t−1: 5k2+b2k2+2bk+1=56⟹k2(5+b2)+2bk−55=0
k2(2b+11)+2bk−55=0
2bk(k+1)+11k2−55=0
b=3 and k=2
t=3
α=t=3
β=2t+1=7
γ=bt+2=3(3)+2=11
α+β+γ=3+7+11=21
Q 66MathematicsSection A • MCQ3d geometry
+4 / -1
Let a line L be perpendicular to both the lines L1:3x+1=5y+3=7z+5 and L2:1x−2=4y−4=7z−6. If θ is the acute angle between the lines L and L3:2x−78=1y−74=2z, then tanθ is equal to:
A
232
B
252
C
352
D
342
Official Correct Answer:Option (B)
Step-by-Step Solution:
The direction vectors of L1 and L2 are:
d1=3i^+5j^+7k^
d2=i^+4j^+7k^
Since L is perpendicular to both L1 and L2, its direction vector d is:
d=d1×d2=i^31j^54k^77
d=i^(35−28)−j^(21−7)+k^(12−5)
d=7i^−14j^+7k^ or u=i^−2j^+k^
L3:2x−87=1y−47=2z
v=2i^+j^+2k^
u⋅v=(1)(2)+(−2)(1)+(1)(2)=2−2+2=2
∣u∣=12+(−2)2+12=6
∣v∣=22+12+22=9=3
cosθ=362
perpendicular=hypotenuse2−base2=(36)2−22
perpendicular=54−4=50=52
tanθ=baseperpendicular=252=25
Q 67MathematicsSection A • MCQlimits continuity and differentiability
+4 / -1
The value of limx→0(x2−sin2xx2sin2x) is:
A
2
B
3
C
4
D
6
Official Correct Answer:Option (B)
Step-by-Step Solution:
L=limx→0x2−sin2xx2sin2x
L=limx→0(x−sinx)(x+sinx)x2sin2x
L=limx→0(xsinx)2⋅(x−sinx)(x+sinx)x4
L=limx→0(xsinx)2⋅(x−sinxx3)⋅(x+sinxx)
L=(1)2⋅(1/61)⋅(1+11)
L=1⋅6⋅21
L=3
Q 68MathematicsSection A • MCQdefinite integration
+4 / -1
The value of the integral ∫−4π4π(1+esinx32cos4x)dx is:
A
4π+2
B
3π+8
C
3π+4
D
4π+3
Official Correct Answer:Option (B)
Step-by-Step Solution:
I=∫−4π4π1+esinx32cos4xdx— (Equation 1)
I=∫−4π4π1+esin(−x)32cos4(−x)dx
I=∫−4π4πesinx+132cos4x⋅esinxdx— (Equation 2)
2I=∫−4π4π1+esinx32cos4x(1+esinx)dx
2I=∫−4π4π32cos4xdx
I=16∫−4π4πcos4xdx
I=32∫04πcos4xdx
cos4x=(21+cos2x)2=41+2cos2x+cos22x
cos4x=41(1+2cos2x+21+cos4x)=81(3+4cos2x+cos4x)
I=32∫04π81(3+4cos2x+cos4x)dx
I=4[3x+2sin2x+4sin4x]04π
I=4(43π+2(1)+0)
I=3π+8
Q 69MathematicsSection A • MCQarea under the curves
+4 / -1
The area of the region {(x,y):0≤y≤6−x,y2≥4x−3,x≥0} is:
A
8
B
9
C
12
D
15
Official Correct Answer:Option (B)
Step-by-Step Solution:
6−y=4y2+3
24−4y=y2+3
y2+4y−21=0
(y+7)(y−3)=0⟹y=3(since y≥0)
The point of intersection is (3,3)
From y=0 to y=3: The region is bounded on the right by the parabola x=4y2+3.
From y=3 to y=6: The region is bounded on the right by the line x=6−y.
Let e be the base of natural logarithm and let f:{1,2,3,4}→{1,e,e2,e3} and g:{1,e,e2,e3}→{1,21,31,41} be two bijective functions such that f is strictly decreasing and g is strictly increasing. If ϕ(x)=[f−1{g−1(21)}]x, then the area of the region R = {(x, y): x2≤y≤ϕ(x), 0≤x≤1} is:
A
3loge(2)3−loge(2)
B
3loge(2)1
C
3+loge(2)
D
2+loge(3)3+loge(2)
Official Correct Answer:Option (A)
Step-by-Step Solution:
The function g:{1,e,e2,e3}→{1,21,31,41} is a strictly increasing bijection
Domain elements: 1<e<e2<e3
Range elements: 41<31<21<1
g(e2)=21⟹∴g−1(21)=e2
The function f:{1,2,3,4}→{1,e,e2,e3} is a strictly decreasing bijection.
Domain elements: 1<2<3<4
Range elements: 1<e<e2<e3
Since it is decreasing, the smallest domain element maps to the largest range element, and vice versa:
∴f−1(e2)=2
ϕ(x)=2x
The area of the bounded region R={(x,y):x2≤y≤2x,0≤x≤1} is:
Area=∫01(2x−x2)dx=[ln22x−3x3]01
Area=(ln22−31)−(ln21−0)=ln21−31
Area=3ln23−ln2=3loge(2)3−loge(2)
Q 71MathematicsSection B • Numericalmatrices and determinants
+4 / -1
Let A=−110100−111 satisfy A2+α(adj(adj(A)))+β(adj(A)adj(adj(A)))=2−20−2002−1−1 for some α,β∈R. Then (α−β)2 is equal to _______.
Answer Format:Enter numerical value rounded to the nearest integer
Let the centre of the circle x2+y2+2gx+2fy+25=0 be in the first quadrant and lie on the line 2x−y=4. Let the area of an equilateral triangle inscribed in the circle be 273. Then the square of the length of the chord of the circle on the line x=1 is _______.
Answer Format:Enter numerical value rounded to the nearest integer
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
The equation of the circle is x2+y2+2gx+2fy+25=0.
Center is C(−g,−f).
Since the center lies in the first quadrant: −g>0⟹g<0 and −f>0⟹f<0.
The center lies on 2x−y=4⟹2(−g)−(−f)=4⟹f=2g+4.
Radius R=g2+f2−25.
Area=433R2
433R2=273⟹R2=36⟹R=6
g2+f2−25=36⟹g2+f2=61
g2+(2g+4)2=61
5g2+16g−45=0
(5g−9)(g+5)=0⟹g=−5(since g<0)
f=2(−5)+4=−6
Thus, the center of the circle is C(−g,−f)=(5,6)
The perpendicular distance (d) from the center (5,6) to the vertical line x=1 is: d=∣5−1∣=4
L=2R2−d2
L2=4(R2−d2)=4(36−16)=4(20)=80
Q 73MathematicsSection B • Numericalvector algebra
+4 / -1
If a=i^+j^+k^, b=j^−k^ and c be three vectors such that a×c=b and a⋅c=3, then c⋅(a−2b) is equal to _______.
Answer Format:Enter numerical value rounded to the nearest integer
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
Expression=c⋅a−2(c⋅b)
Expression=3−2(c⋅b)— (Equation 1)
b=a×c
c⋅b=c⋅(a×c)
c⋅(a×c)=0
⟹c⋅b=0
Expression=3−2(0)=3
Q 74MathematicsSection B • Numericaltrigonometric ratios and identities
+4 / -1
For the functions f(θ)=αtan2θ+βcot2θ, and g(θ)=αsin2θ+βcos2θ, α>β>0, let min0<θ<2πf(θ)=max0<θ<πg(θ). If the first term of a G.P. is (2βα), its common ratio is (α2β) and the sum of its first 10 terms is nm, gcd(m,n)=1, then m+n is equal to _______.
Answer Format:Enter numerical value rounded to the nearest integer
Official Correct Answer:Declared in Solution
Step-by-Step Solution:
2αtan2θ+βcot2θ≥(αtan2θ)(βcot2θ)
2f(θ)≥αβ⟹f(θ)≥2αβ
min0<θ<2πf(θ)=2αβ
g(θ)=αsin2θ+β(1−sin2θ)
g(θ)=(α−β)sin2θ+β
max0<θ<πg(0)=(α−β)(1)+β=α
2αβ=α
4αβ=α2
α=4β⟹αβ=41
First term (a) = 2βα=2β4β=2
Common ratio (r) = α2β=2(41)=21
S10=1−ra(1−r10)
S10=1−212(1−(21)10)=212(1−10241)
S10=4×10241023=2561023
m=1023,n=256
m+n=1023+256=1279
Q 75MathematicsSection B • Numericaldifferential equations
+4 / -1
Let y=y(x) be the solution of the differential equation (x2−xx2−1)dy+(y(x−x2−1)−x)dx=0, x≥1. If y(1)=1, then the greatest integer less than y(5) is _______.
Answer Format:Enter numerical value rounded to the nearest integer