Practice Questions

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

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

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

Q14.In the given electromagnetic wave Ey = 600 sin(ωt −kx)Vm−1 , intensity of the associated light beam is (in W/m2 : (Given ϵ0 = 9 × 10−12C2 N−1 m−2 ) (1) 243 (2) 729 (3) 972 (4) 486

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 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 rectangular loop of length 2. 5 m and width 2 m is placed at 60° to a magnetic field of 4 T. The loop is removed from the field in 10 sec. The average emf induced in the loop during this time is (1) −2 V (2) +2 V (3) +1 V (4) −1 V

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

Q14.In an a.c. circuit, voltage and current are given by: V = 100 sin(100t) V and I = 100 sin(100t + π3 ) mA respectively. The average power dissipated in one cycle is : (1) 5 W (2) 10 W (3) 2. 5 W (4) 25 W

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.A galvanometer having coil resistance 10 Ω shows a full scale deflection for a current of 3 mA . For it to measure a current of 8 A , the value of the shunt should be: (1) 3 × 10−3Ω (2) 4. 85 × 10−3Ω (3) 3. 75 × 10−3Ω (4) 2. 75 × 10−3Ω

Q14.A beam of unpolarised light of intensity 𝐼0 is passed through a polaroid 𝐴 and then through another polaroid 𝐵 which is oriented so that its principal plane makes an angle of 45° relative to that of 𝐴. The intensity of emergent light is : (1) 𝐼0 (2) 𝐼0 4 𝐼0 𝐼0 (3) (4) 2 8

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.A parallel plate capacitor has a capacitance 𝐶= 200 pF. It is connected to 230 V ac supply with an angular frequency 300 rad s-1. The rms value of conduction current in the circuit and displacement current in the capacitor respectively are : JEE Main 2024 (01 Feb Shift 1) JEE Main Previous Year Paper (1) 1 .38 μA and 1 .38 μA (2) 14 .3 μA and 143 μA (3) 13 .8 μA and 138 μA (4) 13 .8 μA and 13 .8 μA

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.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.The primary side of a transformer is connected to 230 V, 50 Hz supply. The turn ratio of primary to secondary winding is 10 : 1. Load resistance connected to the secondary side is 46 Ω. The power consumed in it is: (1) 12 . 5 W (2) 10 . 0 W (3) 11 . 5 W (4) 12 . 0 W

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. 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

Q15.Electromagnetic waves travel in a medium with speed of 1.5 × 108 m s−1 . The relative permeability of the medium is 2.0 . The relative permittivity will be: (1) 2 (2) 4 (3) 5 (4) 1

Q15.A plane electromagnetic wave propagating in x-direction is described by Ey = (200 V m−1) sin[1. 5 × 107t −0. 05x]; The intensity of the wave is : (Use ϵ0 = 8. 85 × 10−12 C2 N−1 m−2 ) (1) 35. 4 W m−2 (2) 53. 1 W m−2 (3) 26. 6 W m−2 (4) 106. 2 W m−2

Q15.Two conducting circular loops A and B are placed in the same plane with their centers coinciding as shown in figure. The mutual inductance between them is : (1) μ0πb2 (2) μo ⋅b2a 2π 2a (3) μ0 2π ⋅a2b (4) μ0πa22b

Q15. List-I List-II EM-Wave Wavelength Range (A) Infra-red (I) < 10−3 nm Match List-I with List-II : (B) Ultraviolet (II) 400 nm to 1 nm (C) X-rays S (III) 1 mm to 700 nm (D) Gamma rays (IV) 1 nm to 10−3 nm (1) (A)-(III), (B)-(II), (C)-(IV), (D)-(I) (2) (A)-(II), (B)-(I), (C)-(IV), (D)-(III) (3) (A)-(IV), (B)-(III), (C)-(II), (D)-(I) (4) (A)-(I), (B)-(III), (C)-(II), (D)-(IV)

Q15.The deflection in moving coil galvanometer falls from 25 divisions to 5 division when a shunt of 24 Ω is applied. The resistance of galvanometer coil will be: (1) 12 Ω (2) 96 Ω (3) 48 Ω (4) 100 Ω