Practice Questions

Q12.A capacitor of capacitance 100 μF is charged to a potential of 12 V and connected to a 6. 4 mH inductor to produce oscillations. The maximum current in the circuit would be : (1) 3. 2 A (2) 1. 5 A (3) 2. 0 A (4) 1. 2 A

Q12.In a metre-bridge when a resistance in the left gap is 2 Ω and unknown resistance in the right gap, the balance length is found to be 40 cm . On shunting the unknown resistance with 2 Ω, the balance length changes by: (1) 22 . 5 cm (2) 20 cm (3) 62 . 5 cm (4) 65 cm JEE Main 2024 (01 Feb Shift 2) JEE Main Previous Year Paper

Q13.An element Δl = Δx^i is placed at the origin and carries a large current I = 10 A. The magnetic field on the y- axis at a distance of 0.5 m from the elements Δx of 1 cm length is: JEE Main 2024 (06 Apr Shift 1) JEE Main Previous Year Paper (1) 4 × 10−8 T (2) 10 × 10−8 T (3) 8 × 10−8 T (4) 12 × 10−8 T

Q13.Three voltmeters, all having different internal resistances are joined as shown in figure. When some potential difference is applied across A and B, their readings are 𝑉1, 𝑉2 and 𝑉3. Choose the correct option. JEE Main 2024 (27 Jan Shift 2) JEE Main Previous Year Paper (1) 𝑉1 = 𝑉2 (2) 𝑉1 ≠𝑉3 - 𝑉2 (3) 𝑉1 + 𝑉2 > 𝑉3 (4) 𝑉1 + 𝑉2 = 𝑉3

Q13.The magnetic moment of a bar magnet is 0.5Am2 . It is suspended in a uniform magnetic field of 8 × 10−2 T. The work done in rotating it from its most stable to most unstable position is: (1) 8 × 10−2 J (2) 4 × 10−2 J (3) Zero (4) 16 × 10−2 J JEE Main 2024 (04 Apr Shift 2) JEE Main Previous Year Paper

Q13.In the given figure R1 = 10Ω, R2 = 8Ω, R3 = 4Ω and R4 = 8Ω . Battery is ideal with emf 12 V . Equivalent resistant of the circuit and current supplied by battery are respectively : (1) 10.5Ω and 1.14 A (2) 12Ω and 1 A (3) 10.5Ω and 1 A (4) 12Ω and 11.4 A

Q13.Two insulated circular loop A and B radius a carrying a current of I in the anti clockwise direction as shown in figure. The magnitude of the magnetic induction at the centre will be: (1) √2μ0I (2) μ0I a 2a (3) μ0I (4) 2μ0I √2a a

Q13.To measure the internal resistance of a battery, potentiometer is used. For R = 10Ω, the balance point is observed at l = 500 cm and for R = 1Ω the balance point is observed at l = 400 cm. The internal resistance of the battery is approximately : (1) 0.2Ω (2) 0.3Ω (3) 0.4Ω (4) 0.1Ω

Q13.A uniform magnetic field of 2 × 10-3 T acts along positive Y-direction. A rectangular loop of sides 20 cm and 10 cm with current of 5 A is in Y-Z plane. The current is in anticlockwise sense with reference to negative X axis. Magnitude and direction of the torque is : (1) 2 × 10-4 N m along positive Z –direction (2) 2 × 10-4 N m along negative Z-direction (3) 2 × 10-4 N m along positive X-direction (4) 2 × 10-4 N m along positive Y-direction π

Q13.Match List I with List II List I List II 1 A. Gauss’s law of magnetostatics i. ∮ →𝐸· d→𝑎= ∫𝜌d𝑉 𝜀0 B. Faraday’s law of electro magnetic induction ii. ∮ →𝐵· d→𝑎= 0 → → -d → C. Ampere’s law iii. ∮ 𝐸· d 𝑙= 𝐵· d →𝑎 d𝑡∫ D. Gauss’s law of electrostatics iv. ∮ →𝐵· d →𝑙= 𝜇0𝐼 Choose the correct answer from the options given below: (1) A-I, B-III, C-IV, D-II (2) A-III, B-IV, C-I, D-II (3) A-IV, B-II, C-III, D-I (4) A-II, B-III, C-IV, D-I

Q13.A galvanometer has a resistance of 50 𝛺 and it allows maximum current of 5 mA. It can be converted into voltmeter to measure upto 100 V by connecting in series a resistor of resistance. (1) 5975 𝛺 (2) 20050 𝛺 (3) 19950 𝛺 (4) 19500 𝛺

Q13.Two charges 𝑞 and 3𝑞 are separated by a distance ‘𝑟’ in air. At a distance 𝑥 from charge 𝑞, the resultant electric field is zero. The value of 𝑥 is : (1) ( 1 + √3 ) (2) 𝑟 𝑟 3 ( 1 + √3 ) 𝑟 (3) (4) 𝑟( 1 + √3 ) ( 1 + √3 ) JEE Main 2024 (31 Jan Shift 1) JEE Main Previous Year Paper

Q13.Two particles X and Y having equal charges are being accelerated through the same potential difference. Thereafter, they enter normally in a region of uniform magnetic field and describes circular paths of radii R1 and R2 respectively. The mass ratio of X and Y is : (1) R2 2 (2) R1 2 ( R1 ) ( R2 ) (3) ( R2R1 ) (4) ( R1R2 ) JEE Main 2024 (29 Jan Shift 2) JEE Main Previous Year Paper

Q13.In an ammeter, 5% of the main current passes through the galvanometer. If resistance of the galvanometer is G, the resistance of ammeter will be: G G (1) (2) 20 199 (3) 199 G (4) 200 G

Q13.The electric current through a wire varies with time as I = I0 + βt, where I0 = 20 A and β = 3 A s−1 . The amount of electric charge crossed through a section of the wire in 20 s is: JEE Main 2024 (29 Jan Shift 1) JEE Main Previous Year Paper (1) 80 C (2) 1000 C (3) 800 C (4) 1600 C

Q13. The equivalent resistance between A and B is : (1) 18Ω (2) 19Ω (3) 25Ω (4) 27Ω

Q13.A long straight wire of radius a carries a steady current I. The current is uniformly distributed across its cross section. The ratio of the magnetic field at a and 2a from axis of the wire is : 2 (1) 1 : 4 (2) 1 : 1 (3) 3 : 4 (4) 4 : 1

Q13.A proton moving with a constant velocity passes through a region of space without any change in its velocity. → → If E and B represent the electric and magnetic fields respectively, then the region of space may have : (A) E = 0, B = 0; (B) E = 0, B ≠0; (C) E ≠0, B = 0; (D) E ≠0, B ≠0 Choose the most appropriate answer from the options given below : (1) (A), (B) and (C) only (2) (A), (C) and (D) only (3) (A), (B) and (D) only (4) (B), (C) and (D) only

Q13.The electrostatic force → and magnetic force acting on a charge q moving with velocity v can be (→F2) (F1) written : (1) →F1 = q →E, →F2 = q(→V × →B) (2) →F1 = q →B, →F2 = q(→B × →V ) (3) →F1 = q →E, →F2 = q(→B × →V ) (4) →F1 = q →V ⋅→E, →F2 = q(→B ⋅→V )

Q13.The magnetic field in a plane electromagnetic wave is By = (3.5 × 10−7) sin (1.5 × 103x + 0.5 × 1011t)T. The corresponding electric field will be : (1) Ey = 10.5 sin (1.5 × 103x + 0.5 × 1011t)Vm−1 (2) Ez = 1.17 sin (1.5 × 103x + 0.5 × 1011t)Vm−1 (3) Ey = 1.17 sin (1.5 × 103x + 0.5 × 1011t)Vm−1 (4) Ez = 105 sin (1.5 × 103x + 0.5 × 1011t)Vm−1

Q13.In a coil, the current changes from −2 A to +2 A in 0.2 s and induces an emf of 0.1 V. The self inductance of the coil is : (1) 4mH (2) 1mH (3) 5mH (4) 2.5mH

Q14. Match List I with List II Choose the correct answer from the options given below: (1) A-I. B-IV, C-II, D-III (2) A-IV. B-I. C-II. D-III (3) A-IV. B-I, C-III, D-II (4) A-I. B-IV, C-III, D-II

Q14.A coil of negligible resistance is connected in series with 90Ω resistor across 120 V, 60 Hz supply. A voltmeter reads 36 V across resistance. Inductance of the coil is : JEE Main 2024 (08 Apr Shift 2) JEE Main Previous Year Paper (1) 0.286H (2) 0.76H (3) 2.86H (4) 0.91H

Q14.A series LR circuit connected with an ac source E = (25 sin 1000t) V has a power factor of 1 . If the source √2 of emf is changed to E = (20 sin 2000t) V, the new power factor of the circuit will be : (1) 1 (2) 1 √2 √3 (3) 1 (4) 1 √5 √7

Q14.An AC voltage 𝑉= 20sin200𝜋𝑡 is applied to a series LCR circuit which drives a current 𝐼= 10sin200π𝑡+ 3 . The average power dissipated is: JEE Main 2024 (31 Jan Shift 2) JEE Main Previous Year Paper (1) 21 . 6 W (2) 200 W (3) 173 . 2 W (4) 50 W