Practice Questions

Q16.For the thin convex lens, the radii of curvature are at 15 cm and 30 cm respectively. The focal length the lens is 20 cm. The refractive index of the material is : (1) 1.2 (2) 1.8 (3) 1.5 (4) 1.4

Q16.When unpolarized light is incident at an angle of 60° on a transparent medium from air. The reflected ray is completely polarized. The angle of refraction in the medium is (1) 30° (2) 60° (3) 90° (4) 45°

Q16.A convex mirror of radius of curvature 30 cm forms an image that is half the size of the object. The object distance is : (1) −45 cm (2) 45 cm (3) −15 cm (4) 15 cm

Q16.Given below are two statements : Statement I : When the white light passed through a prism, the red light bends lesser than yellow and violet. Statement II : The refractive indices are different for different wavelengths in dispersive medium. In the light of the above statements, chose the correct answer from the options given below: (1) Statement I is false but Statement II is true (2) Statement I is true but Statement II is false (3) Both Statement I and Statement II are true (4) Both Statement I and Statement II are false

Q16.A proton and an electron are associated with same de-Broglie wavelength. The ratio of their kinetic energies is: (Assume h=6.63 ×10−34 J s, me = 9.0 × 10−31 kg and mp = 1836 times me ) (1) 1 : √1836 (2) 1 : 18361 (3) 1 : 1 (4) 1: 1836 √1836

Q16.In a plane EM wave, the electric field oscillates sinusoidally at a frequency of 5 × 1010 Hz and an amplitude of 50 V m – 1. The total average energy density of the electromagnetic field of the wave is : [Use 𝜀0 = 8 . 85 × 10 – 12 C2 N-1 m-2] (1) 1 . 106 × 10 – 8 J m – 3 (2) 4 . 425 × 10 – 8 J m – 3 (3) 2 . 212 × 10 – 8 J m – 3 (4) 2 . 212 × 10 – 10 J m – 3 𝐴

Q16.In photoelectric experiment energy of 2.48eV irradiates a photo sensitive material. The stopping potential was measured to be 0.5 V. Work function of the photo sensitive material is : (1) 1.68eV (2) 2.48eV (3) 1.98eV (4) 0.5eV

Q16.The electric field of an electromagnetic wave in free space is represented as →E = E0 cos(ωt −kz)ˆi corresponding magnetic induction vector will be : (1) → (2) → E0 B = E0C B = C cos(ωt −kz)ˆj cos(ωt −kz)ˆj (3) → (4) → E0 B = E0C + B = C + cos(ωt kz)ˆj cos(ωt kz)ˆj JEE Main 2024 (30 Jan Shift 1) JEE Main Previous Year Paper

Q16.When a polaroid sheet is rotated between two crossed polaroids then the transmitted light intensity will be maximum for a rotation of : (1) 60° (2) 30° (3) 90° (4) 45°

Q16.If frequency of electromagnetic wave is 60 MHz and it travels in air along z direction then the corresponding electric and magnetic field vectors will be mutually perpendicular to each other and the wavelength of the wave in m is : (1) 2 . 5 (2) 10 (3) 5 (4) 2

Q17.The threshold frequency of a metal with work function 6 . 63 eV is : (1) 16 × 1015 Hz (2) 16 × 1012 Hz (3) 1 . 6 × 1012 Hz (4) 1 . 6 × 1015 Hz

Q17.Average force exerted on a non-reflecting surface at normal incidence is 2.4 × 10−4 N. If 360 W/cm2 is the light energy flux during span of 1 hour 30 minutes, Then the area of the surface is: (1) 0.2 m2 (2) 20 m2 (3) 0.1 m2 (4) 0.02 m2

Q17.Light emerges out of a convex lens when a source of light kept at its focus. The shape of wavefront of the light is : (1) both spherical and cylindrical (2) plane (3) spherical (4) cylindrical JEE Main 2024 (05 Apr Shift 1) JEE Main Previous Year Paper

Q17.In a photoelectric effect experiment a light of frequency 1 . 5 times the threshold frequency is made to fall on the surface of photosensitive material. Now if the frequency is halved and intensity is doubled, the number of photo electrons emitted will be: (1) Doubled (2) Quadrupled (3) Zero (4) Halved

Q17.A biconvex lens of refractive index 1. 5 has a focal length of 20 cm in air. Its focal length when immersed in a liquid of refractive index 1. 6 will be: (1) −16 cm (2) −160 cm (3) +160 cm (4) +16 cm

Q17.If Mo is the mass of isotope 125 B, MP and Mn are the masses of proton and neutron, then nuclear binding energy of isotope is : (1) (Mo −5Mp)C 2 (2) (5Mp + 7Mn −Mo)C 2 (3) (M0 −12Mn)C 2 (4) (Mo −5Mp −7Mn)C 2

Q17.An effective power of a combination of 5 identical convex lenses which are kept in contact along the principal axis is 25D. Focal length of each of the convex lens is : JEE Main 2024 (04 Apr Shift 1) JEE Main Previous Year Paper (1) 20 cm (2) 50 cm (3) 500 cm (4) 25 cm

Q17.The refractive index of a prism with apex angle 𝐴 is 𝑐𝑜𝑡 2. The angle of minimum deviation is : (1) 𝛿𝑚= 180° - 𝐴 (2) 𝛿𝑚= 180° - 3𝐴 (3) 𝛿𝑚= 180° - 4𝐴 (4) 𝛿𝑚= 180° - 2𝐴

Q17.A proton, an electron and an alpha particle have the same energies. Their de-Broglie wavelengths will be compared as : (1) λα < λp < λe (2) λe > λα > λp (3) λp > λe > λα (4) λp < λe < λα

Q17.Which of the following statement is not true about stopping potential (V0) ? (1) It is 1/ e times the maximum kinetic energy of (2) It increases with increase in intensity of the electrons emitted. incident light. (3) It depends on the nature of emitter material. (4) It depends upon frequency of the incident light.

Q17.An electron revolving in 𝑛th Bohr orbit has magnetic moment 𝜇𝑛. If 𝜇𝑛 ∝ 𝑛𝑥, the value of 𝑥 is: (1) 2 (2) 1 (3) 3 (4) 0

Q17.A nucleus at rest disintegrates into two smaller nuclei with their masses in the ratio of 2 : 1 . After disintegration they will move : (1) in the same direction with same speed. (2) in opposite directions with the same speed. (3) in opposite directions with speed in the ratio of (4) in opposite directions with speed in the ratio of 2 : 1 respectively. 1 : 2 respectively.

Q17.A microwave of wavelength 2 . 0 cm falls normally on a slit of width 4 . 0 cm . The angular spread of the central maxima of the diffraction pattern obtained on a screen 1 . 5 m away from the slit, will be: (1) 30 º (2) 15 º (3) 60 º (4) 45 º

Q17.Which of the following phenomena does not explain by wave nature of light. A. reflection B. diffraction C. photoelectric effect D. interference E. polarization Choose the most appropriate answer from the options given below: (1) E only (2) B, D only (3) C only (4) A, C only

Q17.A convex lens of focal length 40 cm forms an image of an extended source of light on a photoelectric cell. A current I is produced. The lens is replaced by another convex lens having the same diameter but focal length 20 cm. The photoelectric current now is (1) I (2) 4I 2 (3) 2I (4) I