Practice Questions

Q13.A massless square loop, of wire of resistance 10 Ω, supporting a mass of 1 g, hangs vertically with one of its sides in a uniform magnetic field of 103 G, directed outwards in the shaded region. A dc voltage 𝑉 is applied to the loop. For what value of 𝑉, the magnetic force will exactly balance the weight of the supporting mass of 1 g? (If sides of the loop = 10 cm, 𝑔= 10 m s-2) . JEE Main 2023 (30 Jan Shift 1) JEE Main Previous Year Paper 1 (1) 10V (2) 100 V (3) 1 V (4) 10 V

Q13.Let γ1 be the ratio of molar specific heat at constant pressure and molar specific heat at constant volume of a monoatomic gas and γ2 be the similar ratio of diatomic gas. Considering the diatomic gas molecule as a rigid rotator, the ratio γ1 is: γ2 (1) 27 (2) 35 35 27 (3) 25 (4) 21 21 25

Q13.If the r.m.s speed of chlorine molecule is 490 m s−1 at 27oC , the r.m.s speed of argon molecules at the same temperature will be (Atomic mass of argon = 39. 9 u , molecular mass of chlorine = 70. 9 u ) (1) 551. 7 m s−1 (2) 651. 7 m s−1 (3) 451. 7 m s−1 (4) 751. 7 m s−1

Q13.Find the magnetic field at the point P in figure. The curved portion is a semicircle connected to two long straight wires. JEE Main 2023 (01 Feb Shift 1) JEE Main Previous Year Paper 𝜇0𝑖 2 𝜇0𝑖 1 (1) 2𝑟1 + π (2) 2𝑟1 + π 𝜇0𝑖 1 1 𝜇0𝑖 1 1 (3) + (4) + 2𝑟 2 2π 2𝑟 2 π

Q13.At 300 K , the rms speed of oxygen molecules is √α+5α value of α will be (use π = 227 ) (1) 32 (2) 28 (3) 24 (4) 27

Q13.The root mean square velocity of molecules of gas is (1) Proportional to square of temperature ( T 2 ). (2) Inversely proportional to square root of temperature ( ). √1T (3) Proportional to square root of temperature √T . (4) Proportional to temperature (T).

Q13.A Carnot engine operating between two reservoirs has efficiency 1 . When the temperature of cold reservoir 3 raised by x , its efficiency decreases to 1 . The value of x , if the temperature of hot reservoir is 99° C , will be 6 (1) 16. 5 K (2) 33 K (3) 66 K (4) 62 K

Q13.A car P travelling at 20 m s−1 sounds its horn at a frequency of 400 Hz. Another car Q is travelling behind the first car in the same direction with a velocity 40 m s−1 . The frequency heard by the passenger of the car Q is approximately [Take, velocity of sound = 360 m s−1 ] (1) 421 Hz (2) 471 Hz (3) 485 Hz (4) 514 Hz

Q13.A circular loop of radius 𝑅 is carrying current 𝑖 A. The ratio of magnetic field at the centre of circular loop and at a distance 𝑅 from the center of the loop on its axis is : (1) 1: 3√2 (2) 3√2: 2 (3) 2√2: 1 (4) 1: √2 JEE Main 2023 (24 Jan Shift 1) JEE Main Previous Year Paper 10

Q13.The induced emf can be produced in a coil by A. moving the coil with uniform speed inside uniform magnetic field B. moving the coil with non uniform speed inside uniform magnetic field C. rotating the coil inside the uniform magnetic field D. changing the area of the coil inside the uniform magnetic field Choose the correct answer from the options given below: (1) 𝐵 and 𝐶 only (2) 𝐴 and 𝐶 only (3) 𝐶 and 𝐷 only (4) 𝐵 and 𝐷 only

Q13.Given below are two statements: Statement I: If the number of turns in the coil of a moving coil galvanometer is doubled then the current sensitivity becomes double. Statement II: Increasing current sensitivity of a moving coil galvanometer by only increasing the number of turns in the coil will also increase its voltage sensitivity in the same ratio In the light of the above statements, choose the correct answer from the options given below: (1) Statement I is true but Statement II is false (2) Statement I is false but Statement II is true (3) Both Statement I and Statement II are false (4) Both Statement I and Statement II are true

Q13.A simple pendulum with length 100 cm and bob of mass 250 g is executing S.H.M of amplitude 10 cm. The maximum tension in the string is found to be x N . The value of x is _____. 40

Q13.Two simple harmonic waves having equal amplitudes of 8 cm and equal frequency of 10 Hz are moving along the same direction. The resultant amplitude is also 8 cm. The phase difference between the individual waves is _____ degree.

Q13.The current sensitivity of moving coil galvanometer is increased by 25%. This increase is achieved only changing in the number of turns of coils and area of cross section of the wire while keeping the resistance of galvanometer coil constant. The percentage change in the voltage sensitivity will be: (1) +25% (2) -50% (3) -25% (4) Zero

Q13.An electron is moving along the positive x-axis. If uniform magnetic field is applied parallel to the negative z- axis, then A.The electron will experience magnetic force along positive y-axis B.The electron will experience magnetic force along negative y-axis C.The electron will not experience any force in magnetic field D.The electron will continue to move along the positive x-axis E.The electron will move along circular path in magnetic field Choose the correct answer from the option given below: (1) A and E only (2) C and D only (3) B and E only (4) B and D only

Q13.Given below are two statements: Statement I: For diamagnetic substance -1 ≤x < 0, where x is the magnetic susceptibility. Statement II: Diamagnetic substance when placed in an external magnetic field, tend to move from stronger to weaker part of the field. In the light of the above statements, choose the correct answer from the options give below. (1) Both Statement I and Statement II are False (2) Statement I is correct but Statement II is false (3) Statement I is incorrect but Statement II is true (4) Both Statement I and Statement II are true

Q13.A bar magnet with a magnetic moment 5 . 0 A m2 is placed in parallel position relative to a magnetic field of 0 . 4 T. The amount of required work done in turning the magnet form parallel to antiparallel position relative to the field direction is ________. (1) 4 J (2) 1 J (3) 2 J (4) Zero

Q13.For particle P revolving round the centre O with radius of circular path r and regular velocity ω, as shown in below figure, the projection of OP on the x-axis at time t is JEE Main 2023 (08 Apr Shift 2) JEE Main Previous Year Paper (1) x(t) = r cos(ωt −π6 ) (2) x(t) = r cos(ωt + π6 ) (3) x(t) = r sin(ωt + π6 ) (4) x(t) = r cos(ωt)

Q14.A particle is executing simple harmonic motion (SHM). The ratio of potential energy and kinetic energy of the particle when its displacement is half of its amplitude will be (1) 1 : 1 (2) 1 : 3 (3) 2 : 1 (4) 1 : 4

Q14.At a given point of time the value of displacement of a simple harmonic oscillator is given as y = A cos(30°). If amplitude is 40 cm and kinetic energy at that time is 200 J, the value of force constant 1. 0 × 10x N m–1 . The value of x is _____.

Q14.A rod with circular cross-section area 2 cm2 and length 40 cm is wound uniformly with 400 turns of an insulated wire. If a current of 0 . 4 A flows in the wire windings, the total magnetic flux produced inside windings is 4π × 10-6 Wb. The relative permeability of the rod is (Given : Permeability of vacuum μ0 = 4π × 10-7 N A-2) 32 (1) 12 . 5 (2) 5 (3) 125 (4) 5 16

Q14.The displacement equations of two interfering waves are given by y1 = 10 sin (ωt + π3 ) cm, cm respectively. The amplitude of the resultant wave is _____ cm. y2 = 5[sin (ωt) + √3 cos ωt]

Q14.A particle executes simple harmonic motion between x = –A and x = +A. If time taken by particle to go from x = 0 to A2 is 2 s; then time taken by particle in going from x = A2 to A is: (1) 3 s (2) 2 s (3) 1. 5 s (4) 4 s

Q14.The velocity of a particle executing SHM varies with displacement ( x) as 4v2 = 50–x2 . The time period of oscillations is x 7 s. The value of x is ______. [Take π = 227 ]

Q14.A mass m attached to free end of a spring executes SHM with a period of 1 s. If the mass is increased by 3 kg the period of oscillation increases by one second, the value of mass m is ________ kg.