JEE MAIN - Physics (2023 - 25th January Evening Shift)

1

The light rays from an object have been reflected towards an observer from a standard flat mirror, the image observed by the observer are :-

A. Real

B. Erect

C. Smaller in size then object

D. Laterally inverted

Choose the most appropriate answer from the options given below :

Answer
(A)
B and D only
2
A particle executes simple harmonic motion between $$x=-A$$ and $$x=+A$$. If time taken by particle to go from $$x=0$$ to $$\frac{A}{2}$$ is 2 s; then time taken by particle in going from $$x=\frac{A}{2}$$ to A is
Answer
(A)
4 s
3
The distance travelled by a particle is related to time t as $$x=4\mathrm{t}^2$$. The velocity of the particle at t=5s is :-
Answer
(D)
$$\mathrm{40~ms^{-1}}$$
4

Match List I with List II

List I List II
A. Isothermal Process I. Work done by the gas decreases internal energy
B. Adiabatic Process II. No change in internal energy
C. Isochoric Process III. The heat absorbed goes partly to increase internal energy and partly to do work
D. Isobaric Process IV. No work is done on or by the gas

Choose the correct answer from the options given below :

Answer
(C)
A-II, B-I, C-IV, D-III
5
A wire of length 1m moving with velocity 8 m/s at right angles to a magnetic field of 2T. The magnitude of induced emf, between the ends of wire will be __________.
Answer
(C)
16 V
6

Consider a block kept on an inclined plane (incline at 45$$^\circ$$) as shown in the figure. If the force required to just push it up the incline is 2 times the force required to just prevent it from sliding down, the coefficient of friction between the block and inclined plane($$\mu$$) is equal to :

JEE Main 2023 (Online) 25th January Evening Shift Physics - Laws of Motion Question 32 English

Answer
(B)
0.33
7

Match List I with List II

List I List II
A. Gauss's Law in Electrostatics I. $$\oint {\overrightarrow E \,.\,d\overrightarrow l = - {{d{\phi _B}} \over {dt}}} $$
B. Faraday's Law II. $$\oint {\overrightarrow B \,.\,d\overrightarrow A = 0} $$
C. Gauss's Law in Magnetism III. $$\oint {\overrightarrow B \,.\,d\overrightarrow l = {\mu _0}{i_c} + {\mu _0}{ \in _0}{{d{\phi _E}} \over {dt}}} $$
D. Ampere-Maxwell Law IV. $$\oint {\overrightarrow E \,.\,d\overrightarrow s = {q \over {{ \in _0}}}} $$

Choose the correct answer from the options given below :

Answer
(C)
A-IV, B-I, C-II, D-III
8

Every planet revolves around the sun in an elliptical orbit :-

A. The force acting on a planet is inversely proportional to square of distance from sun.

B. Force acting on planet is inversely proportional to product of the masses of the planet and the sun.

C. The Centripetal force acting on the planet is directed away from the sun.

D. The square of time period of revolution of planet around sun is directly proportional to cube of semi-major axis of elliptical orbit.

Choose the correct answer from the options given below :

Answer
(C)
A and D only
9
Two objects are projected with same velocity 'u' however at different angles $$\alpha$$ and $$\beta$$ with the horizontal. If $$\alpha+\beta=90^\circ$$, the ratio of horizontal range of the first object to the 2nd object will be :
Answer
(A)
1 : 1
10

The graph between two temperature scales P and Q is shown in the figure. Between upper fixed point and lower fixed point there are 150 equal divisions of scale P and 100 divisions on scale Q. The relationship for conversion between the two scales is given by :-

JEE Main 2023 (Online) 25th January Evening Shift Physics - Heat and Thermodynamics Question 104 English

Answer
(D)
$${{{t_Q}} \over {100}} = {{{t_P} - 30} \over {150}}$$
11
A point charge of 10 $$\mu$$C is placed at the origin. At what location on the X-axis should a point charge of 40 $$\mu$$C be placed so that the net electric field is zero at $$x=2$$cm on the X-axis?
Answer
(A)
$$x=6$$ cm
12
The resistance of a wire is 5 $$\Omega$$. It's new resistance in ohm if stretched to 5 times of it's original length will be :
Answer
(D)
125
13

Match List I with List II

List I List II
A. Young's Modulus (Y) I. $$\mathrm{[ML^{-1}T^{-1}]}$$
B. Co-efficient of Viscosity ($$\eta$$) II. $$\mathrm{[ML^2T^{-1}]}$$
C. Planck's Constant (h) III. $$\mathrm{[ML^{-1}T^{-2}]}$$
D. Work function ($$\varphi $$) IV. $$\mathrm{[ML^2T^{-2}]}$$

Choose the correct answer from the options given below :

Answer
(D)
A-III, B-I, C-II, D-IV
14

Statement I : When a Si sample is doped with Boron, it becomes P type and when doped by Arsenic it becomes N-type semi conductor such that P-type has excess holes and N-type has excess electrons.

Statement II : When such P-type and N-type semi-conductors, are fused to make a junction, a current will automatically flow which can be detected with an externally connected ameter.

In the light of above statements, choose the most appropriate answer from the options given below

Answer
(C)
Statement I is correct but statement II is incorrect
15
According to law of equipartition of energy the molar specific heat of a diatomic gas at constant volume where the molecule has one additional vibrational mode is :-
Answer
(D)
$$\frac{7}{2}R$$
16

A body of mass is taken from earth surface to the height h equal to twice the radius of earth (R$$_e$$), the increase in potential energy will be :

(g = acceleration due to gravity on the surface of Earth)

Answer
(D)
$$\frac{2}{3}mgR_e$$
17
For a moving coil galvanometer, the deflection in the coil is 0.05 rad when a current of 10 mA is passes through it. If the torsional constant of suspension wire is $$4.0\times10^{-5}\mathrm{N~m~rad^{-1}}$$, the magnetic field is 0.01T and the number of turns in the coil is 200, the area of each turn (in cm$$^2$$) is :
Answer
(D)
1.0
18

Given below are two statements :

Statement I : Stopping potential in photoelectric effect does not depend on the power of the light source.

Statement II : For a given metal, the maximum kinetic energy of the photoelectron depends on the wavelength of the incident light.

In the light of above statements, choose the most appropriate answer from the options given below

Answer
(C)
Both Statement I and Statement II are correct
19

The energy levels of an atom is shown in figure.

JEE Main 2023 (Online) 25th January Evening Shift Physics - Atoms and Nuclei Question 77 English

Which one of these transitions will result in the emission of a photon of wavelength 124.1 nm?

Given (h = 6.62 $$\times$$ 10$$^{-34}$$ Js)

Answer
(D)
D
20

Two long parallel wires carrying currents 8A and 15A in opposite directions are placed at a distance of 7 cm from each other. A point P is at equidistant from both the wires such that the lines joining the point P to the wires are perpendicular to each other. The magnitude of magnetic field at P is _____________ $$\times~10^{-6}$$ T.

(Given : $$\sqrt2=1.4$$)

Answer
68
21
A capacitor has capacitance 5$$\mu$$F when it's parallel plates are separated by air medium of thickness d. A slab of material of dielectric constant 1.5 having area equal to that of plates but thickness $$\frac{d}{2}$$ is inserted between the plates. Capacitance of the capacitor in the presence of slab will be __________ $$\mu$$F.
Answer
6
22

An object is placed on the principal axis of convex lens of focal length 10cm as shown. A plane mirror is placed on the other side of lens at a distance of 20 cm. The image produced by the plane mirror is 5cm inside the mirror. The distance of the object from the lens is ___________ cm.

JEE Main 2023 (Online) 25th January Evening Shift Physics - Geometrical Optics Question 67 English

Answer
30
23

Two cells are connected between points A and B as shown. Cell 1 has emf of 12 V and internal resistance of 3$$\Omega$$. Cell 2 has emf of 6V and internal resistance of 6$$\Omega$$. An external resistor R of 4$$\Omega$$ is connected across A and B. The current flowing through R will be ____________ A.

JEE Main 2023 (Online) 25th January Evening Shift Physics - Current Electricity Question 90 English

Answer
1
24
A series LCR circuit is connected to an AC source of 220 V, 50 Hz. The circuit contains a resistance R = 80$$\Omega$$, an inductor of inductive reactance $$\mathrm{X_L=70\Omega}$$, and a capacitor of capacitive reactance $$\mathrm{X_C=130\Omega}$$. The power factor of circuit is $$\frac{x}{10}$$. The value of $$x$$ is :
Answer
8
25
If a solid sphere of mass 5 kg and a disc of mass 4 kg have the same radius. Then the ratio of moment of inertia of the disc about a tangent in its plane to the moment of inertia of the sphere about its tangent will be $$\frac{x}{7}$$. The value of $$x$$ is ___________.
Answer
5
26
A body of mass 1 kg collides head on elastically with a stationary body of mass 3 kg. After collision, the smaller body reverses its direction of motion and moves with a speed of 2 m/s. The initial speed of the smaller body before collision is ___________ ms$$^{-1}$$.
Answer
4
27
A spherical drop of liquid splits into 1000 identical spherical drops. If u$$_\mathrm{i}$$ is the surface energy of the original drop and u$$_\mathrm{f}$$ is the total surface energy of the resulting drops, the (ignoring evaporation), $${{{u_f}} \over {{u_i}}} = \left( {{{10} \over x}} \right)$$. Then value of x is ____________ :
Answer
1