Practice Questions

Q16.The two light beams having intensities 𝐼 and 9𝐼 interfere to produce a fringe pattern on a screen. The phase 𝜋 difference between the beams is at point 𝑃 and 𝜋 at point 𝑄. Then the difference between the resultant 2 intensities at 𝑃 and 𝑄 will be : (1) 2𝐼 (2) 6𝐼 (3) 5𝐼 (4) 7𝐼

Q16.The kinetic energy of emitted electron is E when the light incident on the metal has wavelength λ . To double the kinetic energy, the incident light must have wavelength: (1) hc (2) hcλ Eλ−hc Eλ+hc (3) hλ (4) hcλ Eλ+hc Eλ−hc

Q16.In young's double slit experiment, the fringe width is 12 mm. If the entire arrangement is placed in water of refractive index 4 , then the fringe width becomes (in mm) 3 (1) 16 (2) 9 (3) 48 (4) 12

Q16.A light whose electric field vectors are completely removed by using a good polaroid, allowed to incident on the surface of the prism at Brewster's angle. Choose the most suitable option for the phenomenon related to the prism. (1) Reflected and refracted rays will be (2) Wave will propagate along the surface of prism. perpendicular to each other. (3) No refraction, and there will be total reflection of (4) No reflection. and there will be total transmission light. of light.

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

Q16.Given below are two statements : Statement I: A time varying electric field is a source of changing magnetic field and vice-versa. Thus a disturbance in electric or magnetic field creates EM waves. Statement II: In a material medium, the EM wave travels with speed v = 1 . √μ0ϵ0 JEE Main 2022 (27 Jun Shift 2) JEE Main Previous Year Paper 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) Both statement I and statement II are false (3) Statement I is correct but statement II is false (4) Statement I is incorrect but statement II is true

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.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

Q16.For a series LCR circuit, I vs ω curve is shown (a) To the left of ωr , the circuit is mainly capacitive. (b) To the left of ωr , the circuit is mainly inductive. (c) At ωr , impedance of the circuit is equal to the resistance of the circuit. (d) At ωr , impedance of the circuit is 0 . Choose the most appropriate answer from the options given below. (1) (a) and (d) only (2) (b) and (d) only (3) (a) and (c) only (4) (b) and (c) only

Q16.In young's double slit experiment performed using a monochromatic light of wavelength λ , when a glass plate (μ = 1. 5) of thickness xλ is introduced in the path of the one of the interfering beams, the intensity at the position where the central maximum occurred previously remains unchanged. The value of x will be (1) 3 (2) 2 (3) 1. 5 (4) 0. 5

Q17.Light enters from air into a given medium at an angle of 45° with interface of the air-medium surface. After refraction, the light ray is deviated through an angle of 15° from its original direction. The refractive index of the medium is : (1) 1 . 732 (2) 1 . 333 (3) 1 . 414 (4) 2 . 732

Q17.The equation 𝜆= nm can be used to find the de-Broglie wavelength of an electron. In this equation 𝑥 x stands for : Where, 𝑚= mass of electron 𝑃= momentum of electron 𝐾= Kinetic energy of electron 𝑉= Accelerating potential in volts for electron (1) √𝑚𝐾 (2) √𝑃 (3) √𝐾 (4) √𝑉

Q17.Let K1 and K2 be the maximum kinetic energies of photo-electrons emitted when two monochromatic beams of wavelength λ1 and λ2 , respectively are incident on a metallic surface. If λ1 = 3λ2 then : (1) K1 > K23 (2) K1 < K23 (3) K1 = K23 (4) K2 = K13

Q17.Consider a light ray travelling in air is incident into a medium of refractive index √2n. The incident angle is twice that of refracting angle. Then, the angle of incidence will be (1) sin−1 √n (2) cos−1( √2n ) (3) sin−1(√2n) (4) 2 cos−1(√n2 )

Q17.Find the ratio of energies of photons produced due to transition of an election of hydrogen atom from its(i) second permitted energy level to the first level, and (ii) the highest permitted energy level to the first permitted level. (1) 3 : 4 (2) 4 : 3 (3) 1 : 4 (4) 4 : 1

Q17.A nucleus of mass 𝑀 at rest splits into two parts having masses 𝑀' and 2𝑀' 𝑀' < 𝑀. The ratio of de Broglie 3 3 wavelength of two parts will be (1) 1: 2 (2) 2: 1 (3) 1: 1 (4) 2: 3

Q17.The speed of light in media ′A′ and ′B′ are 2. 0 × 1010 cm s−1 and 1. 5 × 1010 cm s−1 respectively. A ray of light enters from the medium B to A at an incident angle ′θ′. If the ray suffers total internal reflection, then (1) θ = sin−1( 34 ) (2) θ > sin−1( 32 ) (3) θ > sin−1( 34 ) (4) θ < sin−1( 43 )

Q17.A proton, a neutron, an electron and an 𝛼-particle have same energy. If 𝜆𝑝, 𝜆𝑛, 𝜆𝑒 and 𝜆𝛼 are the de Broglie's wavelengths of proton, neutron, electron and 𝛼 particle respectively, then choose the correct relation from the following (1) 𝜆𝑝= 𝜆𝑛> 𝜆𝑒> 𝜆𝛼 (2) 𝜆𝑎< 𝜆𝑛< 𝜆𝑝< 𝜆𝑒 (3) 𝜆𝑒< 𝜆𝑝= 𝜆𝑛> 𝜆𝛼 (4) 𝜆𝑒= 𝜆𝑝= 𝜆𝑛= 𝜆𝛼. 𝑅

Q17.A convex lens has power P . It is cut into two halves along its principal axis. Further one piece (out of the two halves) is cut into two halves perpendicular to the principal axis (as shown in figures). Choose the incorrect option for the reported pieces. (1) Power of L1 = P2 (2) Power of L2 = P2 (3) Power of L3 = P2 (4) Power of L1 = P

Q17.Using Young's double slit experiment, a monochromatic light of wavelength 5000Å produces fringes of fringe width 0. 5 mm. If another monochromatic light of wavelength 6000Å is used and the separation between the slits is doubled, then the new fringe width will be (1) 0. 5 mm (2) 1. 0 mm (3) 0. 6 mm (4) 0. 3 mm

Q17.An electron (mass m) with an initial velocity →v= v0ˆi(v0 > 0) is moving in an electric field → E = −E0ˆi(E0 > 0) where E0 is constant. If at t = 0 , de-Broglie wavelength is λ0 = mv0h , then its de-Broglie wavelength after time t is given by (1) λ0 (2) λ0(1 + eE0tmv0 ) (3) λ0t (4) λ0eE0t (1+ mv0 )

Q17.An electron with speed v and a photon with speed c have the same de-Broglie wavelength. If the kinetic energy and momentum of electron are Ee and Pe and that of photon are Eph and Pph respectively. Which of the JEE Main 2022 (26 Jun Shift 1) JEE Main Previous Year Paper following is correct? (1) Eph Ee = 2cv (2) EphEe = 2cv (3) pph pe = 2cv (4) pphpe = 2cv

Q17.With reference to the observations in photo-electric effect, identify the correct statements from below: A. The square of maximum velocity of photoelectrons varies linearly with frequency of incident light. B. The value of saturation current increases on moving the source of light away from the metal surface. C. The maximum kinetic energy of photo-electrons decreases on decreasing the power of LED (light emitting diode) source of light. D. The immediate emission of photo-electrons out of metal surface can not be explained by particle nature of light/electromagnetic waves. E. Existence of threshold wavelength can not be explained by wave nature of light/electromagnetic waves. Choose the correct answer from the options given below: (1) A and B only (2) A and E only (3) C and E only (4) D and E only