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Quantum Physics Quiz | objective questions | Physics General Knowledge Questions | MCQ

1 >>work function of a metal is the ?
  • (A) energy required by an electron to get absorbed in the metal surface
  • (B) energy required by an electron to escape from the metal surface
  • (C) minimum energy required by an electron to escape from the metal surface
  • (D) maximum energy required by an electron to escape from the metal surface
2 >>In which case is electron emission from a metal not known? ?
  • (A) Illuminating a metal surface with suitable light
  • (B) Heating the metal sufficiently
  • (C) Applying a very strong magnetic field to a metal
  • (D) Applying a very strong electric field to a metal
3 >>Photoelectric effect is ?
  • (A) emission of electrons by glass when illuminated by light of suitable frequency
  • (B) emission of electrons by metals when heated
  • (C) emission of electrons by insulators when illuminated by light of suitable frequency
  • (D) emission of electrons by metals when illuminated by light of suitable frequency
4 >>Photoelectric effect is possible ?
  • (A) with only visible
  • (B) with only ultraviolet
  • (C) with both visible and uv depending on the metal
  • (D) with only white light
5 >>In Photoelectric effect ?
  • (A) light is converted into electrical energy
  • (B) electrical energy is converted into heat
  • (C) electrical energy is converted magnetic field energy
  • (D) electrical energy is converted into light energy








6 >>n the experimental set up for studying photoelectric effect, if keeping the frequency of the incident radiation and the accelerating potential fixed, the intensity of light is varied, then ?
  • (A) photocurrent decreases nonlinearly with intensity
  • (B) photocurrent remains same with intensity
  • (C) photocurrent decreases linearly with intensity
  • (D) photocurrent increases linearly with intensity
7 >>Stopping potential in the experimental set up ?
  • (A) negative potential V0 given to the plate A for which the photocurrent stops or becomes zero
  • (B) positive potential V0 given to the plate A for which the photocurrent saturates
  • (C) positive potential V0 given to the plate A for which the photocurrent stops or becomes zero
  • (D) positive potential V0 given to the plate A for which the photocurrent stops increasing
8 >>For a given frequency of light and a positive plate potential in the set up , If the intensity of light is increased then ?
  • (A) current is inversely proportional to intensity
  • (B) current is unaffected by more intensity
  • (C) current is more with more intensity
  • (D) current is less with more intensity
9 >>In various experiments on photo electricity the stopping potential for a given frequency of the incident radiation ?
  • (A) is proportional to radiation intensity
  • (B) is independent of the radiation intensity
  • (C) is independent of radiation intensity
  • (D) is inversely proportional to radiation intensity
10 >>In various experiments on photo electricity dealing with the stopping potential dependence on frequency of incident radiation , the conclusion was that stopping potential ?
  • (A) depends on the light intensity
  • (B) is independent of frequency
  • (C) depends on the frequency
  • (D) depends on the initial current
11 >>According to the Einstein’s model minimum energy needed for the electron to escape from a metal surface having work function ϕ0, the electron is emitted with maximum kinetic energy Kmax = ?
  • (A) hν - ϕ0
  • (B) hν
  • (C) hν + ϕ0
  • (D) hν - 2 ϕ0
12 >>According to the Einstein’s model the threshold frequency for a metal having work function ϕ0 is given by ?
  • (A) ϕ0h +100
  • (B) h/∅0
  • (C) ∅0/h
  • (D) ϕ0h
13 >>In interaction of radiation with matter, radiation behaves as if it is made up of particles called ?
  • (A) electron
  • (B) proton
  • (C) bosons
  • (D) positron





14 >>Each photon has the same speed but different ?
  • (A) rest mass
  • (B) radius
  • (C) frequency
  • (D) energy
15 >>Mirage is due to ?
  • (A) unequal heating of different parts of the atmosphere
  • (B) magnetic disturbances in the atmosphere
  • (C) depletion of ozone layer in the atmosphere
  • (D) equal heating of different parts of the atmosphere
16 >>Photon has a charge of ?
  • (A) 0
  • (B) +2e; e= charge on electron
  • (C) -e; e= charge on electron
  • (D) -2e; e= charge on electron
17 >>Photons can be ?
  • (A) deflected by magnetic fields
  • (B) scattered
  • (C) deflected by magnetic fields
  • (D) deflected by electric fields
18 >>In a photon-particle collision (such as photon-electron collision) the quantity which is not conserved is ?
  • (A) number of photons
  • (B) total energy
  • (C) None of the above
  • (D) total momentum
19 >>De Broglie proposed that the wave length λ associated with a particle of momentum p = mv is given as ?
  • (A) h/2mv
  • (B) mv/h
  • (C) 2h/mv
  • (D) h/mv
20 >>Davisson Germer experiment proves that ?
  • (A) electrons exhibit particle nature
  • (B) protons exhibit wave nature
  • (C) neutrons exhibit wave nature
  • (D) electrons exhibit wave nature










21 >>A photon is ?
  • (A) a quantum of light energy
  • (B) a quantum of matter
  • (C) an instrument for measuring light intensity
  • (D) a positive charged particle
22 >>A photoelectric cell converts ?
  • (A) light energy into electric energy
  • (B) electric into light energy
  • (C) light energy into heat energy
  • (D) light energy into sound energy
23 >>The momentum of photon having energy E is ?
  • (A) E/h
  • (B) 0
  • (C) E/c2
  • (D) E/c
24 >>Photo-electric effect can be explained only by assuming that light ?
  • (A) is a form of longitudinal waves
  • (B) consists of quanta
  • (C) can be polarized
  • (D) is a form of transverse waves
25 >>The energy of a photon corresponding to the visible light of maximum wavelength is approximately ?
  • (A) 3.2 eV
  • (B) 1.6 ev
  • (C) 1 eV
  • (D) 7 eV
26 >>In order to increase the kinetic energy of ejected photoelectrons, there should be an increase in ?
  • (A) intensity of radiation
  • (B) Both the wavelength and intensity of radiation
  • (C) wavelength of radiation
  • (D) frequency of radiation
27 >>If h is Planck’s constant, the momentum of a photon of wavelength 0.01 A0 is ?
(A) 1012h
(B) h
(C) 102h
(D) 1012h
28 >>Planck’s constant has the dimensions of ?

  • (A) energy
  • (B) angular momentum
  • (C) forcr
  • (D) linear momentum





29 >>Number of ejected photoelectrons increases with increase ?
  • (A) in frequency of light
  • (B) in intensity of light
  • (C) never
  • (D) in wavelength of light
30 >>A photon behaves as if it had a mass equal to ?
  • (A) hv/c
  • (B) c2/hv
  • (C) hv/c2
  • (D) hvc
31 >>If the energy of a photon corresponding to a wave length of 6000 A0 is 3.32 ×1019 joule, the photon energy for a wavelength of 4000 A0
  • (A) 2.22 ×1019 joules
  • (B) 5.98×1019 joules
  • (C) 6.98×1019 joules
  • (D) 4.98×1019 joules
32 >>The work function for aluminium surface is 4.2 eV. The cutoff wavelength for the photo electric effect for the surface is ?
  • (A) 3100 A0
  • (B) 2400 A0
  • (C) 1500 A0
  • (D) 2955 A0
33 >>The work function of a photoelectric material is 3.32 eV. The threshold frequency will be equal to ?
  • (A) 9 ×1014 HZ
  • (B) 6 ×1014 HZ
  • (C) 8 ×1014 HZ
  • (D) 7 ×1014 HZ
34 >>Light of wavelength 4000 A0 is incident on a metal plate whose work function is 2 eV. The maximum kinetic energy of the emitted photoelectrons would be ?
  • (A) 0.5eV
  • (B) 1.5 eV
  • (C) 1.1eV
  • (D) 2.0eV
35 >>Given h = 6.6 ×10−34 joule sec, the momentum of each photon in a given radiation is 3.3 ×10−29 kg metre/sec. The frequency of radiation is ?
  • (A) 1.7 ×1013 Hz
  • (B) 1.8 ×1013 Hz
  • (C) 1.5 ×1013 Hz
  • (D) 1.6 ×1013 Hz
36 >>If 109 electrons move out of a body to another body every second, how much time is approximately required to get a total charge of 1 C on the other body? ?
  • (A) 180 years
  • (B) 220 years
  • (C) 200 years
  • (D) 120 years
37 >>If the wavelength of light falling on a surface is increased from 3000 A0 to 3040 A0, then what will be the corresponding change in the stopping potential (given that hc = 12.4×107 eVÅ)? ?
  • (A) (-7.5) ×10−12 V
  • (B) (-8.5) ×10−12V
  • (C) ( -5.5) ×10−12 V
  • (D) (-6.5) ×10−12 V
38 >>If the wavelength of light incident on photo-electric cell be reduced from 4000A0 to3600A0,then what will be the change in the cut off potential. ?
  • (A) 0.42Volt
  • (B) 0.43Volt
  • (C) 0.34Volt
  • (D) 0.30Volt
39 >>If the voltage across the electrodes of a cathode ray tube is 500 volts then energy gained by the electrons is ?
  • (A) 7 ×10−17 J
  • (B) 9 ×10−17 J
  • (C) 8 ×10−17 J
  • (D) 6 ×10−17 J
40 >>Which of the following is correct about photoelectric cell? ?
  • (A) converts light energy into heat energy
  • (B) converts electric into light energy
  • (C) converts light energy into sound energy
  • (D) converts light energy into electric energy



 
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