381. In a photoelectric effect monochromatic light is incident on a metal surface. If the incident light of twice the intensity but of same wavelength the kinetic energy of the emitted electron_______________?
A. Becomes double
B. Remains same
C. Becomes half
D. First increases then decrease because of the curvilinear graph

382. If the wavelength of incident radiation is increased in photoemission then_________________?
A. The maximum kinetic energy of the photoelectrons increases
B. The minimum kinetic energy of the photoelectrons decreases
C. The minimum kinetic energy of the photoelectrons increases
D. The average kinetic energy of the photoelectrons decreases

383. If a photon is reflected from the mirror then the change in momentum of each photon is_______________?
A. Zero
B. Double
C. Half
D. 1

384. If n number of the photon is striking on a metal surface then total momentum exerted is_______________?
A. p
B. n
C. 0
D. None

385. A photon of wavelength 900nm behaves like a particle of mass______________?
A. 5.53 x 10-36kg
B. 0 kg.
C. 2.46 x 10-36kg
D. 1.84 x 10-44kg

386. The velocity of a particle of mass m of de-Broglie wavelength λ is______________?
A. v = 3 ×× 106 ms-1
B. v = 2 ×× 10 ms-1
C. v = 2 ×× 6 ms-1
D. v = 2 ×× 106 ms-1

387. In Davisson-Germer experiment the diffracted proton from crystal shows______________?
A. Particle property
B. Wave property
C. Light property
D. Quantum property

388. If a diffraction grating is placed in the path of a light beam it reveals______________?
A. Wave property
B. Particle property
C. Energy particle
D. Electromagnetic wave property

389. In an electron microscope, we use energetic particles because of______________?
A. Penetrating power is high
B. Kinetic energy is large
C. Wavelength is very short
D. All the above reasons

390. In the electron microscope, electric & magnetic fields are used as_______________?
A. Electromagnetic gun
B. Source of electromagnetic waves
C. Deflecting charged particle
D. Converging source of electrons