Practice Questions

Q12.An alternating voltage 𝑉( 𝑡) = 220sin100𝜋t volt is applied to a purely resistive load of 50 𝛺. The time taken for the current to rise from half of the peak value to the peak value is: (1) 5 ms (2) 3 . 3 ms (3) 7 . 2 ms (4) 2 . 2 ms

Q12.A current of 200 μA deflects the coil of a moving coil galvanometer through 60°. The current to cause 𝜋 deflection through radian is 10 (1) 30 μA (2) 120 μA (3) 60 μA (4) 180 μA

Q12.The value of unknown resistance (x) for which the potential difference between B and D will be zero in the arrangement shown, is : (1) 3Ω (2) 42Ω (3) 9Ω (4) 6Ω

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

Q12.The resistance per centimeter of a meter bridge wire is 𝑟, with 𝑋 𝛺 resistance in left gap. Balancing length from left end is at 40 cm with 25 𝛺 resistance in right gap. Now the wire is replaced by another wire of 2𝑟 resistance per centimeter. The new balancing length for same settings will be at (1) 20 cm (2) 10 cm (3) 80 cm (4) 40 cm

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

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.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.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.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.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.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.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.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.Paramagnetic substances: A. align themselves along the directions of external magnetic field. B. attract strongly towards external magnetic field. C. has susceptibility little more than zero. D. move from a region of strong magnetic field to weak magnetic field. Choose the most appropriate answer from the options given below: (1) A, B, C Only (2) A, B, C, D (3) A, C Only (4) B, D Only

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 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.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.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 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.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