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# JEE Main 2021 Question Paper with Solutions PDF-25 Feb P2

Get free JEE Main 2021 question paper with solutions here. This blog contains solutions of 25 February 2021 question paper.

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Posted by Mahak Jain, 31/3/2021

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JEE Main 2021 Question paper (Official) with solutions for February session has been released. It is released separately for four session in February, March, April and May sessions. JEE Main is conducted for providing admission into UG engineering (B.Tech) / architecture courses (B.Arch). These courses are offered by various IITs, NITs and IIITs and other government and non-government engineering institutions. JEE Main question paper and answer key is released by the National Testing Agency (NTA). And solutions are prepared by Kunduz tutors for you. Through this blog, candidates can get the JEE Main 2021 question paper with solutions and also previous year answer key and question papers with all solutions.

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## JEE Main 2021 Question Paper with Solutions- 25 February Shift 2

### Physics JEE Main 2021 Question Paper with Solutions 25 Feb Shift 1

#### Question 1

The truth table for the following logic circuit is

#### Question 2

Match List I with List II.

Choose the correct answer from the options given below :

1. (a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)

2. (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii)

3. (a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)

4. (a)-(ii), (b)-(i), (c)-(iv), (d)-(iii)

#### Question 3

A stone is dropped from the top of a building. When it crosses a point 5 m below the top, another stone starts to fall from a point 25 m below the top. Both stones reach the bottom of building simultaneously. The height of the building is

1. 35 m
2. 45 m
3. 25 m
4. 50 m

#### Question 4

The point A moves with a uniform speed along the circumference of a circle of radius 0.36 m and covers 30° in 0.1 s. The perpendicular projection ‘P’ from ‘A’ on the diameter MN represents the simple harmonic motion of ‘P’. The restoration force per unit mass when P touches M will be

1. 9.87 N
2. 50 N
3. 100 N
4. 0.49 N

#### Question 5

An LCR circuit contains resistance of 110 Ω and a supply of 220 V at 300 rad/s angular frequency. If only capacitance is removed from the circuit, current lags behind the voltage by 45°. If on the other hand, only inductor is removed the current leads by 45° with the applied voltage. The rms current flowing in the circuit will be

1. 1.5 A
2. 1 A
3. 2 A
4. 2.5 A

#### Question 6

Consider the diffraction pattern obtained from the sunlight incident on a pinhole of diameter 0.1 μm. If the diameter of the pinhole is slightly increased, it will affect the diffraction pattern such that

1. Its size decreases, and intensity decreases

2. Its size increases, and intensity increases

3. Its size increases, but intensity decreases

4. Its size decreases, but intensity increases

#### Question 7

Thermodynamic process is shown below on a P-V diagram for one mole of an ideal gas. If V2 = 2V1 then the ratio of temperature T2/T1 is

1. √2
2. 2
3. 1/2
4. 1/√2

#### Question 8

An electron of mass me and a proton of mass mp=1836me are moving with the same speed. The ratio of their de Broglie wavelength λelectron / λproton will be

1. 1/1836
2. 918
3. 1
4. 1836

#### Question 9

The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition from n = 2 to n = 1 state is

1. 490.7 nm
2. 121.8 nm
3. 913.3 nm
4. 194.8 nm

#### Question 10

For extrinsic semiconductors; when doping level is increased;

1. Fermi-level of p-type semiconductors will go downward and Fermi-level of n-type semiconductor will go upward.

2. Fermi-level of p and n-type semiconductors will not be affected.

3. Fermi-level of both p-type and n-type semiconductors will go upward for T > TF K and downward for T < TF K, where TF is Fermi temperature.

4. Fermi-level of p-type semiconductor will go upward and Fermi-level of n-type semiconductors will go downward.

#### Question 11

Y = Asin(ωt + Φ0) is the time-displacement equation of a SHM. At t = 0 the displacement of the particle is Y=A/2 and it is moving along negative x-direction. Then the initial phase angle Φ0 will be:

1. π/6
2. 2π/3
3. 5π/6
4. π/3

#### Question 12

The stopping potential for electrons emitted from a photosensitive surface illuminated by light of wavelength 491 nm is 0.710 V. When the incident wavelength is changed to a new value, the stopping potential is 1.43 V. The new wavelength is :

1. 329 nm
2. 400 nm
3. 382 nm
4. 309 nm

#### Question 13

If a message signal of frequency ‘fm’ is amplitude modulated with a carrier signal of frequency ‘fc’ and radiated through an antenna, the wavelength of the corresponding signal in air is:

1. c/fc
2. c/fm
3. c/(fm+fc)
4. c/(fc-fm)

#### Question 14

Given below are two statements :

Statement I : In a diatomic molecule, the rotational energy at a given temperature obeys Maxwell’s distribution.

Statement II : In a diatomic molecule, the rotational energy at a given temperature equals the translational kinetic energy for each molecule.

In the light of the above statements, choose the correct answer from the options given below:

1. Both Statement I and Statement II are false.
2. Statement I is false but Statement II is true.
3. Statement I is true but Statement II is false.
4. Both Statement I and Statement II are true.

#### Question 15

A charge ‘q’ is placed at one corner of a cube as shown in figure. The flux of electrostatic field E through the shaded area is:

1. q/4ε0
2. q/24ε0
3. q/48ε0
4. q/8ε0

#### Question 16

An electron with kinetic energy K1 enters between parallel plates of a capacitor at an angle ‘α’ with the plates. It leaves the plates at angle ‘β’ with kinetic energy K2. Then the ratio of kinetic energies K1 : K2 will be :

1. cosβ/sinα
2. cosβ/cosα
3. cos2β/cos2α
4. sin2β/cos2α

#### Question 17

In a ferromagnetic material, below the curie temperature, a domain is defined as :

1. a macroscopic region with randomly oriented magnetic dipoles.

2. a macroscopic region with consecutive magnetic dipoles oriented in opposite direction.

3. a macroscopic region with saturation magnetization.

4. a macroscopic region with zero magnetization.

#### Question 18

Two identical springs of spring constant ‘2k’ are attached to a block of mass m and to fixed support (see figure). When the mass is displaced from equilibrium position on either side, it executes simple harmonic motion. The time period of oscillations of this system is :

1. π√(m/k)
2. π√(m/2k)
3. 2π√(m/2k)
4. 2π√(m/k)

#### Question 19

A sphere of radius ‘a’ and mass ‘m’ rolls along a horizontal plane with constant speed v0. It encounters an inclined plane at angle θ and climbs upward. Assuming that it rolls without slipping, how far up the sphere will travel?

1. v02/5gsinθ
2. v02/2gsinθ
3. 10v02/7gsinθ
4. 2v02/5gsinθ

#### Question 20

If e is the electronic charge, c is the speed of light in free space and h is Planck’s constant, the quantity e2/(4πε0hc) has dimensions of :

1. [M L T–1]
2. [M L T0]
3. [L C–1]
4. [M0 L0 T0]

#### Question 21

The wavelength of an X-ray beam is 10 Å. The mass of a fictitious particle having the same energy as that of the X-ray photons is xh/3 kg. The value of x is _. (h = Planck’s constant)

#### Question 22

Two identical conducting spheres with negligible volume have 2.1 nC and –0.1 nC charges, respectively. They are brought into contact and then separated by a distance of 0.5 m. The electrostatic force acting between the spheres is __ × 10–9 N.

#### Question 23

The percentage increase in the speed of transverse waves produced in a stretched string if the tension is increased by 4% will be __%.

#### Question 24

The peak electric field produced by the radiation coming from the 8 W bulb at a distance of 10 m is

The efficiency of the bulb is 10% and it is a point source. The value of x is __.

#### Question 26

The initial velocity vi required to project a body vertically upward from the surface of the earth to reach a height of 10R, where R is the radius of the earth, may be described in terms of escape velocity ve such that vi=ve√(x/y). The value of x will be

#### Question 27

Two small spheres each of mass 10 mg are suspended from a point by threads 0.5 m long. They are equally charged and repel each other to a distance of 0.20 m. The charge on each of the sphere is a/21 ⨯10–8 C. The value of ‘a’ will be. [Given g = 10 ms–2]

#### Question 28

A reversible heat engine converts one-fourth of the heat input into work. When the temperature of the sink is reduced by 52 K, its efficiency is doubled. The temperature in Kelvin of the source will be __.

#### Question 29

A current of 6 A enters one corner P of an equilateral triangle PQR having 3 wires of resistance 2Ω each and leaves by the corner R. The currents i1 in ampere is __.

#### Question 30

Two particles having masses 4 g and 16 g respectively are moving with equal kinetic energies. The ratio of the magnitudes of their momentum is n : 2. The value of n will

## JEE Main Frequently Asked Questions (FAQs)

Question 1: When is JEE Main 2021 exams?

Answer: National Testing Agency has announced dates for all phases of JEE Main. First phase is in February 2021 (23, 24, 25 and 26). Second phase is in March 2021 (15, 16, 17 & 18) , third in April 2021 (27, 28, 29 & 30) and fourth in May 2021 (24, 25, 26, 27 & 28). To get more details about JEE Main click here.

Question 2: Can I challenge JEE Main 2021 answer key? How?

Answer: Yes, candidates who have objection to the answer key given by National Testing Agency can go to jeemain.nta.nic.in , from where they can challenge answer key.

Question 3: Does National Testing Agency refund JEE Mains 2021 answer key fees.

Answer: Yes, National Testing Agency refund fees if objection is found valid with proper supporting documents.

Question 4: Who will conduct JEE Main 2021 Counseling?

Answer: Joint Seat Allocation Authority (JoSAA) is responsible for counseling of JEE Main 2021 qualified students.

## Importance of Doubt Clearing with Solving JEE Main Question Paper

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