Q.1. Electron volt (eV) is the measure of
(A) charge
(B) potential difference
(C) current
(D) energy
Ans :- (D)
Q.2. Dimension of plank constant is
(A) ML²T⁻¹
(B) ML²T⁻²
(C) MLT⁻¹
(D) MLT⁻²
Ans :- (A)
Q.3. On the basis of photo electric effect, light is
(A) Wave
(B) Particle
(C) Both
(D) None of these
Ans :- (B)
Q.4. The energy of emitted photo electron depends up on
(A) Intensity of light
(B) Wave length of light
(C) Work – function of metal
(D) None of these
Ans :- (B)
Q.5. The number of Photons of frequency 10¹⁴ Hz in radiation of 6.62 J will be
(A) 10¹⁰
(B) 10¹⁵
(C) 10²⁰
(D) 10²⁵
Ans :- (C)
Q.6. Dimensional formula of the Planck’s constant is
(A) [ML²T⁻¹]
(B) [ML²T⁻²]
(C) [MLT⁻¹]
(D) none of these
Ans :- (A)
Q.7. de Broglie relation is
(A) λ = h/P
(B) λ = P/h
(C) λ = h × P
(D) λ = h²/ P²
Ans :- (A)
Q.8. The discovery of photoelectric effect is first observed by
(A) Einstein
(B) Heinrich Hertz
(C) J.J Thomson
(D) none of these
Ans :- (B)
Q.9. In compton effect, the value of compton shift is maximum for photon – scattering angle of
(A) 0⁰
(B) 45⁰
(C) 90⁰
(D) 180⁰
Ans :- (D)
Q.10. When a photon stimulates the emission of another photon, the two photons have
(A) same energy
(B) same direction
(C) same wavelength
(D) all of above
Ans:- (D)
Q.11. The energy (E) of photon is
(A) hv
(B) hv/c
(C) 1/2 mv
(D) h/p
Ans :- (A)
Q.12. The SI unit of Planck’s constant is
(A) Js
(B) Ws
(C) Js⁻¹
(D) Js⁻²
Ans :- (A)
Q.13. Work function is measured in
(A) electron – volt
(B) watt
(C) volt
(D) none of these
Ans :- (A)
Q.14. What is the minimum value of compton shift ?
(A) zero
(B) 2h/m₀C
(C) m₀C/2h
(D) none of these
Ans :- (A)
Q.15. What is the maximum value of compton shift ?
(A) zero
(B) 2h/m₀C
(C) m₀C/2h
(D) none of these
Ans :- (B)
Q.16. The de Broglie wavelength of a particle of K.E. ‘K’ is λ. What would be the wavelength of the particle if its K.E. were K/4 ?
(A) λ/2
(B) λ/4
(C) λ
(D) 2λ
Ans :- (D)
Q.17. An electron is accelerate through a potential difference of 300V. What is the wavelength of the electron ?
(A) 71 A
(B) 7.1 A
(C) 0.71 A
(D) none of these
Ans :- (C)
Q.18. What is the frequency associated with a photon of energy 3.3×10⁻¹⁰ J ?
(A) 5×10²³ Hz
(B) 5×10²² Hz
(C) 5×10¹¹ Hz
(D) none of these
Ans :- (A)
Q.19. λ is proportional to
(A) 1/E for both photon and particles
(B) 1/E for photon and 1/√E for particles
(C) 1/√E for both photon and particles
(D) none of these
Ans :- (B)
Q.20. When ultraviolet ray are incident on a metal plate, photo-electric effect does not occur. It occurs by incidence of
(A) infrared rays
(B) X-rays
(C) radiowaves
(D) microwave
Ans :- (B)
Q.21. The de Broglie wavelength of a moving particle becomes larger if its
(A) mass is increased
(B) momentum is reduced
(C) momentum is increased
(D) velocity is increased
Ans :- (B)
Q.22. If the intensity of incident radiation is doubled, what changes occur in the photoelectric current ?
(A) photoelectric current is doubled
(B) photo electric current is halved
(C) both ‘A’ and ‘B’
(D) none of these
Ans :- (A)
Q.23. If particles are moving with same velocity, then which has maximum de Broglie wavelength ?
(A) proton
(B) α-particle
(C) neutron
(D) β-particle
Ans :- (D)
Q.24. If an electron be accelerated from rest by a potential difference of 1 volt, its kinetic energy will be
(A) 1.6×10⁻¹⁹ joule
(B) 7.6×10⁻¹⁹ joule
(C) 1.6×10⁻¹³ joule
(D) none of these
Ans :- (A)
Q.25. A particle is dropped from a height H . The de Broglie wavelength of the particle as a function of height is proportional to
(A) H
(B) H¹/²
(C) H⁰
(D) H⁻¹/²
Ans :- (D)
Q.26. Photo cell is converted
(A) mechanical energy into electrical energy
(B) electrical energy into light energy
(C) light energy into electrical energy
(D) electrical energy into mechanical energy
Ans :- (C)
Q.27. The work function of metal A is twice the work function of metal B. The ratio of threshold wavelength for metal A to that of metal B is
(A) 1:2
(B) 2:1
(C) 1:4
(D) 1:1
Ans :- (A)
Q.28. The de Broglie wavelength associated with an electron accelerated through a potential difference ‘V’ is λ . What will be its wavelength when the accelerating potential difference is increased to 4V?
(A) λ
(B) 2λ
(C) λ/2
(D) none of these
Ans :- (C)
Q.29. Photoelectric effect reveals the
(A) wave nature of radiation
(B) particle nature of radiation
(C) both ‘A’ and ‘B’
(D) e.m. nature of radiation
Ans :- (B)
Q.30. An electron and an α-particle have the same de Broglie wavelength associated with them. What is the ratio of the kinetic energy?
(A) me:mₐ
(B) 1:1
(C) 2me:mₐ
(D) mₐ:me
Ans :- (D)
Q.31. What is the momentum of a photon of frequency ν
(A) hν
(B) C/hν
(C) h/C
(D) none of these
Ans :- (A)
Q.32. The energy of a photon of green light of wavelenght 5500 A is
(A) 2.20 eV
(B) 2.0 eV
(C) 2.25 eV
(D) 2.3 eV
Ans :- (C)
Q.33. If the maximum kinetic energy of electron emitted in a photocell is 5 eV, what is the stopping potential ?
(A) 10 V
(B) 0.5 V
(C) 15 V
(D) 5 V
Ans :- (D)
Q.34. X-rays are made up of
(A) negatively charged particles
(B) positively charged particles
(C) electromagnetic radiations
(D) neutrons
Ans :- (C)