Practice Questions

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 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.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.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.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.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.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.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.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.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.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 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

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

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.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

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.The following figure represents two biconvex lenses L1 and L2 having focal length 10 cm and 15 cm respectively. The distance between L1&L2 is : (1) 10 cm (2) 35 cm (3) 25 cm (4) 15 cm

Q14.In a co-axial straight cable, the central conductor and the outer conductor carry equal currents in opposite directions. The magnetic field is zero : (1) outside the cable (2) inside the outer conductor (3) inside the inner conductor (4) in between the two conductors

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.To measure the temperature coefficient of resistivity α of a semiconductor, an electrical arrangement shown in the figure is prepared. The arm BC is made up of the semiconductor. The experiment is being conducted at 25°C and resistance of the semiconductor arm is 3 m𝛺. Arm BC is cooled at a constant rate of 2 °C s-1. If the galvanometer G shows no deflection after 10 s, then α is: (1) -2 × 10-2 ∘C-1 (2) -1 . 5 × 10-2 ∘C-1 (3) -1 × 10-2 ∘C-1 (4) -2 . 5 × 10-2 ∘C-1

Q14.Given below are two statements : Statement (I) : When currents vary with time, Newton's third law is valid only if momentum carried by the electromagnetic field is taken into account. Statement (II) : Ampere's circuital law does not depend on Biot-Savart's law. In the light of the above statements, choose the correct answer from the options given below : (1) Both Statement I and Statement II are true (2) Statement I is true but Statement II is false (3) Both Statement I and Statement II are false (4) Statement I is false but Statement II is true

Q14.A rigid wire consists of a semicircular portion of radius 𝑅 and two straight sections. The wire is partially immerged in a perpendicular magnetic field 𝐵= 𝐵0 ^j as shown in figure. The magnetic force on the wire if it has a current 𝑖 is : (1) -𝑖𝐵𝑅 ^j (2) 2𝑖𝐵𝑅 ^j (3) 𝑖𝐵𝑅 ^j (4) -2𝑖𝐵𝑅 ^ j

Q14.A series LCR circuit is subjected to an ac signal of 200 V, 50 Hz. If the voltage across the inductor (L = 10mH) is 31.4 V, then the current in this circuit is _____ . (1) 68 A (2) 63 A (3) 10 A (4) 10 mA JEE Main 2024 (05 Apr Shift 2) JEE Main Previous Year Paper

Q14.A LCR circuit is at resonance for a capacitor C , inductance L and resistance R. Now the value of resistance is halved keeping all other parameters same. The current amplitude at resonance will be now: JEE Main 2024 (08 Apr Shift 1) JEE Main Previous Year Paper (1) Zero (2) same (3) halved (4) double