Practice Questions

Q14.A direct current of 4 A and an alternating current of peak value 4 A flow through resistance of 3 Ω and 2 Ω respectively. The ratio of heat produced in the two resistances in same interval of time will be : (1) 3 : 2 (2) 3 : 1 (3) 3 : 4 (4) 4 : 3

Q14.Given below are two statements : One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : In an uniform magnetic field, speed and energy remains the same for a moving charged particle. Reason (R): Moving charged particle experiences magnetic force perpendicular to its direction of motion. JEE Main 2022 (24 Jun Shift 1) JEE Main Previous Year Paper (1) Both Assertion and Reason are true and Reason is (2) Both Assertion and Reason are true but Reason is the correct explanation of Assertion. NOT the correct explanation of Assertion. (3) Assertion is true but Reason is false. (4) Assertion is false but Reason is true.

Q14.The equation of current in a purely inductive circuit is 5sin49𝜋𝑡- 30°. If the inductance is 30mH then the equation for the voltage across the inductor, will be (1) 1 . 47sin49𝜋𝑡- 30° (2) 1 . 47sin49𝜋𝑡+ 60° (3) 23 . 1sin49𝜋𝑡- 30° (4) 23 . 1sin49𝜋𝑡+ 60°

Q15.A charge particle moves along circular path in a uniform magnetic field in a cyclotron. The kinetic energy of the charge particle increases to 4 times its initial value. What will be the ratio of new radius to the original radius of circular path of the charge particle? (1) 1 : 1 (2) 1 : 2 (3) 2 : 1 (4) 1 : 4

Q15.The de Broglie wavelengths for an electron and a photon are λe and λp respectively. For the same kinetic energy of electron and photon, which of the following presents the correct relation between the de Broglie wavelengths of two? (1) λp ∝λ2e (2) λp ∝λe (3) λp ∝√λe (4) λp ∝√1λe

Q15.Identify the correct statements from the following descriptions of various properties of electromagnetic waves. A. In a plane electromagnetic wave electric field and magnetic field must be perpendicular to each other and direction of propagation of wave should be along electric field or magnetic field. B. The energy in electromagnetic wave is divided equally between electric and magnetic fields. C. Both electric field and magnetic field are parallel to each other and perpendicular to the direction of propagation of wave. D. The electric field, magnetic field and direction of propagation of wave must be perpendicular to each other. E. The ratio of amplitude of magnetic field to the amplitude of electric field is equal to speed of light. Choose the most appropriate answer from the options given below: (1) D only (2) B and D only (3) B, C and E only (4) A, B and E only

Q15.When you walk through a metal detector carrying a metal object in your pocket, it raises an alarm. This phenomenon works on (1) Electromagnetic induction (2) Resonance in ac circuits (3) Mutual induction in ac circuits (4) interference of electromagnetic waves

Q15.Two long current carrying conductors are placed parallel to each other at a distance of 8 cm between them. The magnitude of magnetic field produced at mid-point between the two conductors due to current flowing in JEE Main 2022 (29 Jun Shift 2) JEE Main Previous Year Paper them is 300 μT. The equal current flowing in the two conductors is : (1) 30 A in the same direction. (2) 60 A in the opposite direction. (3) 30 A in the opposite direction. (4) 300 A in the opposite direction.

Q15.A beam of light travelling along X -axis is described by the electric field Ey = 900 sin ω(t −xc ). The ratio of electric force to magnetic force on a charge q moving along Y -axis with a speed of 3 × 107 m s−1 will be : [Given speed of light = 3 × 108 m s−1 ] (1) 1 : 1 (2) 1 : 10 (3) 10 : 1 (4) 1 : 2

Q15.Two coils of self inductance L1 and L2 are connected in series combination having mutual inductance of the coils as M . The equivalent self inductance of the combination will be (1) 1 + 1 + M1 (2) L1 + L2 −2M L1 L2 (3) L1 + L2 + M (4) L1 + L2 + 2M JEE Main 2022 (26 Jun Shift 2) JEE Main Previous Year Paper

Q15.The magnetic field of a plane electromagnetic wave is given by → B = 2 × 10−8 sin(0. 5 × 103x + 1. 5 × 1011t)ˆj T. The amplitude of the electric field would be (1) 6 Vm−1 along x-axis (2) 3 Vm−1 along z-axis (3) 6 Vm−1 along z-axis (4) 2 × 10−8 Vm−1 along z-axis

Q15.The interference pattern is obtained with two coherent light sources of intensity ratio 4: 1. And the ratio 𝐼max + 𝐼min is 5 Then, the value of 𝑥 will be equal to : 𝐼max - 𝐼min 𝑥. (1) 3 (2) 4 (3) 2 (4) 1

Q15.A wire 𝑋 of length 50 cm carrying a current of 2 A is placed parallel to a long wire 𝑌 of length 5 m. The wire 𝑌 carries a current of 3 A. The distance between two wires is 5 cm and currents flow in the same direction. The force acting on the wire 𝑌 is : ​ (1) 1 . 2 × 10-5 N directed towards wire 𝑋. (2) 1 . 2 × 10-4 N directed away from wire 𝑋. (3) 1 . 2 × 10-4 N directed towards wire 𝑋. (4) 2 . 4 × 10-5 N directed towards wire 𝑋.

Q15.Sun light falls normally on a surface of area 36 cm2 and exerts an average force of 7. 2 × 10−9 N within a time period of 20 minutes. Considering a case of complete absorption, the energy flux of incident light is (1) 25. 92 × 102 W cm−2 (2) 8. 64 × 10−6 W cm−2 (3) 6. 0 W cm−2 (4) 0. 06 W cm−2

Q15.As shown in the figure, after passing through the medium 1. The speed of light 𝑣2 in medium 2 will be : (Given 𝑐= 3 × 108 m s-1 ) (1) 1 . 0 × 108 m s-1 (2) 0 . 5 × 108 m s-1 (3) 1 . 5 × 108 m s-1 (4) 3 . 0 × 108 m s-1

Q15.The difference of speed of light in the two media 𝐴 and 𝐵𝑣𝐴- 𝑣𝐵 is 2 . 6 × 107 m s-1. If the refractive index of medium 𝐵 is 1 . 47, then the ratio of refractive index of medium 𝐵 to medium 𝐴 is: (Given : speed of light in vacuum 𝑐= 3 × 108 m s-1) (1) 1 . 303 (2) 1 . 318 (3) 1 . 13 (4) 0 . 12

Q15.An EM wave propagating in x-direction has a wavelength of 8 mm. The electric field vibrating y-direction has maximum magnitude of 60 Vm−1 . Choose the correct equations for electric and magnetic fields if the EM wave is propagating in vacuum : j V m−1 (1) Ey = 60 sin[ π4 × 103(x −3 × 108t)]ˆj V m−1 (2) Ey = 60 sin[ π4 × 103(x −3 × 108t)]ˆ Bz = 2 sin[ π4 × 103(x −3 × 108t)]ˆk T Bz = 2 × 10−7 sin[ π4 × 103(x −3 × 108t)]ˆk T (3) Ey = 2 × 10−7 sin[ π4 × 103(x −3 × 108t)]ˆj V m−1(4) Ey = 2 × 10−7 sin[ π4 × 104(x −4 × 108t)]ˆj V m−1 Bz = 60 sin[ π4 × 103(x −3 × 108t)]ˆk T Bz = 60 sin[ π4 × 104(x −4 × 108t)]ˆk T

Q15.The RMS value of conduction current in a parallel plate capacitor is 6 . 9 𝜇A. The capacity of this capacitor, if it is connected to 230 V AC supply with an angular frequency of 600 rad s-1, will be (1) 5pF (2) 50pF (3) 100pF (4) 200pF

Q16.The power of a lens (biconvex) is 1. 25 m−1 in particular medium. Refractive index of the lens is 1. 5 and radii of curvature are 20 cm and 40 cm respectively. The refractive index of surrounding medium: JEE Main 2022 (28 Jul Shift 2) JEE Main Previous Year Paper (1) 1. 0 (2) 97 (3) 3 (4) 4 2 3

Q16.A microscope was initially placed in air (refractive index 1 ). It is then immersed in oil (refractive index 2 ). For a light whose wavelength in air is λ, calculate the change of microscope's resolving power due to oil and choose the correct option (1) Resolving power will be 1 in the oil than it was (2) Resolving power will be twice in the oil than it 4 in the air was in the air. (3) Resolving power will be four times in the oil than (4) Resolving power will be 1 in the oil than it was 2 it was in the air. in the air.

Q16.A resistance of 40 Ω is connected to a source of alternating current rated 220 V, 50 Hz. Find the time taken by the current to change from its maximum value to the rms value : (1) 2. 5 ms (2) 1. 25 ms (3) 2. 5 s (4) 0. 25 s

Q16.A wave of frequency = 3 GHz , strikes a particle of size ( 1001 ) th of (1) Diffraction (2) Scattering (3) Reflection (4) Refraction

Q16.Light travels in two media 𝑀1 and 𝑀2 with speeds 1 . 5 × 108 m s-1 and 2 . 0 × 108 m s-1 respectively. The critical angle between them is 3 (1) tan-1 (2) tan-12 √7 3 (3) cos-13 (4) sin-12 4 3

Q16.Given below are two statements : Statement I: The electric force changes the speed of the charged particle and hence changes its kinetic energy; whereas the magnetic force does not change the kinetic energy of the charged particle. Statement II: The electric force accelerates the positively charged particle perpendicular to the direction of electric field. The magnetic force accelerates the moving charged particle along the direction of magnetic field. In the light of the above statements, choose the most appropriate answer from the options given below : (1) Both Statement I and Statement II are correct. (2) Both Statement I and Statement II are incorrect. (3) Statement I is correct but Statement II is (4) Statement I is incorrect but Statement II is incorrect. correct.

Q16.Two coherent sources of light interfere. The intensity ratio of two sources is 1 : 4. For this interference pattern if the value of Imax+Imin is equal to 2α+1 , then α will be Imax−Imin β+3 β (1) 1. 5 (2) 2 (3) 0. 5 (4) 1