Practice Questions

Q12.For designing a voltmeter of range 50 V and an ammeter of range 10 mA using a galvanometer which has a coil of resistance 54 Ω showing a full scale deflection for 1 mA as in figure. (A) for voltmeter R ≈50 kΩ (B) for ammeter r ≈0. 2 Ω (C) for ammeter r ≈6 Ω (D) for voltmeter R ≈5 kΩ (E) for voltmeter R ≈500 Ω Choose the correct answer from the options given below: (1) (A) and (C) (2) (C) and (E) (3) (C) and (D) (4) (A) and (B)

Q12.The charge flowing in a conductor changes with time as 𝑄𝑡= 𝛼𝑡- 𝛽𝑡2 + 𝛾𝑡3, where 𝛼, 𝛽 and 𝛾 are constants. Minimum value of current is: (1) 3𝛽2 (2) 𝛾2 𝛼- 𝛼- 𝛾 3𝛽 (3) 𝛽- 𝛼2 (4) 𝛼- 𝛽2 3𝛾 3𝛾

Q12.In the network shown below, the charge accumulated in the capacitor in steady state will be: (1) 10 . 3 𝜇C (2) 4 . 8 𝜇C (3) 12 𝜇C (4) 7 . 2𝜇C

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 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.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.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 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.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.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.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.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)

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.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.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

Q14.A person observes two moving trains, A reaching the station and B leaving the station with equal speed of 30 m s−1 . If both trains emit sounds with frequency 300 Hz, (Speed of sound : 330 m s−1 ) approximate difference of frequencies heard by the person will be : (1) 33 Hz (2) 55 Hz (3) 80 Hz (4) 10 Hz

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.The free space inside a current carrying toroid is filled with a material of susceptibility 2 × 10-2. The percentage increase in the value of magnetic field inside the toroid will be (1) 0 . 2% (2) 0 . 1% (3) 2% (4) 1%

Q14.Match the List-I with List-II. List I List II A AC generator I Presence of both L and C B Transformer II Electromagnetic Induction C Resonance phenomenon to occur III Quality factor D Sharpness of resonance IV Mutual Inductance Choose the correct answer from the options given below: (1) A-IV, B-II, C-I, D-III (2) A-II, B-I, C-III, D-IV (3) A-II, B-IV, C-I, D-III (4) A-IV, B-III, C-I, D-II

Q14.In the given circuit, the current I through the battery will be (1) 2. 5 A (2) 1 A (3) 2 A (4) 1. 5 A

Q14.The engine of a train moving with speed 10 m s−1 towards a platform sounds a whistle at frequency 400 Hz . The frequency heard by a passenger inside the train is: (Neglect air speed. Speed of sound in air = 330 m s−1 ) (1) 400 Hz (2) 200 Hz (3) 412 Hz (4) 388 Hz

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 energy of an electromagnetic wave contained in a small volume oscillates with (1) Double the frequency of the wave (2) The frequency of the wave (3) Half the frequency of the wave (4) Zero frequency

Q15.Two polaroids 𝐴 and 𝐵 are placed in such a way that the pass-axis of polaroids are perpendicular to each other. Now, another polaroid 𝐶 is placed between 𝐴 and 𝐵 bisecting angle between them. If intensity of unpolarised light is 𝐼0 then intensity of transmitted light after passing through polaroid 𝐵 will be : (1) 𝐼0 (2) 𝐼0 4 2 𝐼0 (3) (4) Zero 8

Q15.In a series 𝐿𝑅 circuit with 𝑋𝐿= 𝑅, power factor is 𝑃1. If a capacitor of capacitance 𝐶 with 𝑋𝐶= 𝑋𝐿 is added to the circuit the power factor becomes 𝑃2. The ratio of 𝑃1 to 𝑃2 will be : (1) 1: 3 (2) 1: √2 (3) 1: 1 (4) 1: 2