Practice Questions

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.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 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. 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 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 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.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 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 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.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 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.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.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

Q15.A coil is placed perpendicular to a magnetic field of 5000 T. When the field is changed to 3000 T in 2 s, an induced emf of 22 V is produced in the coil. If the diameter of the coil is 0 . 02 m, then the number of turns in the coil is: (1) 7 (2) 70 (3) 35 (4) 140

Q15.If the total energy transferred to a surface in time 𝑡 is 6 . 48 × 105 J, then the magnitude of the total momentum delivered to this surface for complete absorption will be : (1) 2 . 46 × 10-3 kg m s-1 (2) 2 . 16 × 10-3 kg m s-1 (3) 1 . 58 × 10-3 kg m s-1 (4) 4 . 32 × 10-3 kg m s-1

Q15.UV light of 4.13eV is incident on a photosensitive metal surface having work function 3.13eV. The maximum kinetic energy of ejected photoelectrons will be: (1) 4.13eV (2) 3.13eV (3) 1eV (4) 7.26eV

Q15.Primary coil of a transformer is connected to 220 V AC . Primary and secondary turns of the transforms are 100 and 10 respectively. Secondary coil of transformer is connected to two series resistances as shown in figure. The output voltage (V0) is : (1) 7 V (2) 15 V (3) 44 V (4) 22 V . The

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

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.A transformer has an efficiency of 80% and works at 10 V and 4 kW . If the secondary voltage is 240 V, then the current in the secondary coil is: (1) 1 . 59 A (2) 13 . 33 A (3) 1 . 33 A (4) 15 . 1 A

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.An object is placed in a medium of refractive index 3. An electromagnetic wave of intensity 6 × 108 W m-2 falls normally on the object and it is absorbed completely. The radiation pressure on the object would be (speed of light in free space = 3 × 108 m s-1 ): (1) 36 N m-2 (2) 18 N m-2 (3) 6 N m-2 (4) 2 N m-2

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.In series LCR circuit, the capacitance is changed from 𝐶 to 4𝐶. To keep the resonance frequency unchanged, the new inductance should be : 1 (1) reduced by 4𝐿 (2) increased by 2𝐿 (3) reduced by 3 (4) increased to 4𝐿 4𝐿 o

Q15.A plane electromagnetic wave of frequency 35 MHz travels in free space along the X -direction. At a → particular point (in space and time) E = 9. 6ˆj V m−1 . The value of magnetic field at this point is: (1) 3. 2 × 10−8ˆk T (2) 3. 2 × 10−8ˆi (3) 9. 6ˆj T (4) 9. 6 × 10−8ˆk T