Class 12 Dual Nature Of Radiation And Matter CBSE Questions & Answers

Class 12 · Dual Nature Of Radiation And Matter

This is Physics Class 12 Dual Nature Of Radiation and Matter CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
If a potential of \({\rm{1}}{0^{\rm{7}}}\) volts is applied across the electrodes of a CRT, then speed attained by the electrons is approximately (given: \({e \over m} = \) 1.76 \( \times {\rm{ 1}}{0^{{\rm{11}}}}\) C/kg)
  • A
    1.8 \( \times {\rm{1}}{0^{\rm{9}}}{\rm{m }}{{\rm{s}}^{ - {\rm{1}}}}\)
  • B
    1.9 \( \times {\rm{1}}{0^{\rm{9}}}{\rm{m }}{{\rm{s}}^{ - {\rm{1}}}}\)
    Correct
  • C
    1.85 \( \times {\rm{1}}{0^{\rm{9}}}{\rm{m }}{{\rm{s}}^{ - {\rm{1}}}}\)
  • D
    1.75 \( \times {\rm{1}}{0^{\rm{9}}}{\rm{m }}{{\rm{s}}^{ - {\rm{1}}}}\)
2
Energy of a photon of green light of wavelength 5500 is (given: h = 6.62 \( \times {\rm{1}}{0^{ - {\rm{34}}}}{\rm{J }}{{\rm{s}}^{ - {\rm{1}}}})\) approximately
  • A
    2.26 eV
    Correct
  • B
    3.01eV
  • C
    2.81ev
  • D
    2.93 eV
3
Wavelength associated with a photon having energy 4.14eV is
  • A
    5800 \(\mathop A\limits^0 \)
  • B
    5000 \(\mathop A\limits^0 \)
  • C
    3000 \(\mathop A\limits^0 \)
  • D
    4000 \(\mathop A\limits^0 \)
    Correct
4
If the work function of a material is 2eV, then minimum frequency of light required to emit photo-electrons is
  • A
    4.8 \( \times {\rm{ 1}}{0^{{\rm{14}}}}{\rm{Hz}}\)
    Correct
  • B
    4.6 \( \times {\rm{ 1}}{0^{{\rm{14}}}}{\rm{Hz}}\)
  • C
    4.4 \( \times {\rm{ 1}}{0^{{\rm{14}}}}{\rm{Hz}}\)
  • D
    5.0 \( \times {\rm{ 1}}{0^{{\rm{14}}}}{\rm{Hz}}\)
5
If the threshold wavelength of radiations required to eject a photoelectron from a metal surface is 6 \( \times {\rm{1}}{0^{ - {\rm{7}}}}\) m, then work function of the metal is
  • A
    3.6 \( \times {\rm{ 1}}{0^{ - {\rm{19}}}}\) J
  • B
    3.3 \( \times {\rm{ 1}}{0^{ - {\rm{19}}}}\) J
    Correct
  • C
    3.5 \( \times {\rm{ 1}}{0^{ - {\rm{19}}}}\) J
  • D
    3.4 \( \times {\rm{ 1}}{0^{ - {\rm{19}}}}\) J
6
If work function of a metal surface is 3.45 eV ,then maximum wavelength of a photon required to eject a photoelectron is
  • A
    4.0 \( \times {\rm{ 1}}{0^{ - {\rm{7}}}}\)m
  • B
    3.6 \( \times {\rm{ 1}}{0^{ - {\rm{7}}}}\) m
    Correct
  • C
    3.6 \( \times {\rm{ 1}}{0^{ - {\rm{7}}}}\) m
  • D
    3.4 \( \times {\rm{ 1}}{0^{ - {\rm{7}}}}\) m
7
Threshold frequency of a photon required to eject a photoelectron from the surface of cesium is
  • A
    4.3 \( \times {\rm{1}}{0^{{\rm{14}}}}\) Hz
    Correct
  • B
    4.5 \( \times {\rm{1}}{0^{{\rm{14}}}}\)Hz
  • C
    4.4 \( \times {\rm{1}}{0^{{\rm{14}}}}\)Hz
  • D
    4.6 \( \times {\rm{1}}{0^{{\rm{14}}}}\)Hz
8
If work function of a metal plate is negligible then the K.E.of the photoelectrons emitted when radiations of 1000 \(\mathop A\limits^0 \) are incident on the metal surface is
  • A
    11.6 eV
  • B
    14.4 eV
  • C
    12.4 eV
    Correct
  • D
    13.6 eV
9
Maximum velocity of photoelectrons emitted from a metal surface having work function 4 eV is (given: frequency of incident radiations is \({\rm{1}}{0^{{\rm{15}}}}\) Hz)
  • A
    None of these.
  • B
    2 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{m }}{{\rm{s}}^{ - {\rm{1}}}}\)
  • C
    2 \( \times {\rm{ 1}}{0^{\rm{5}}}{\rm{m }}{{\rm{s}}^{ - {\rm{1}}}}\)
    Correct
  • D
    3 \( \times {\rm{ 1}}{0^{\rm{5}}}{\rm{m }}{{\rm{s}}^{ - {\rm{1}}}}\)
10
When ultraviolet light of wavelength 1000 \(\mathop A\limits^0 \) is incident on molybdenum, then the maximum velocity of ejected electron (given: work function of molybdenum = 5.0eV) is
  • A
    1.6 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{cm }}{{\rm{s}}^{ - {\rm{1}}}}\)
    Correct
  • B
    1.8 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{cm }}{{\rm{s}}^{ - {\rm{1}}}}\)
  • C
    1.7 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{cm }}{{\rm{s}}^{ - {\rm{1}}}}\)
  • D
    1.9 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{cm }}{{\rm{s}}^{ - {\rm{1}}}}\)
11
If threshold wavelength for tungsten is 2300 \(\mathop A\limits^0 \), then energy of the electrons emitted by UV light of wavelength 1800 \(\mathop A\limits^0 \) is
  • A
    2.3 \( \times {\rm{ 1}}{0^{ - {\rm{12}}}}\) erg
  • B
    2.1 \( \times {\rm{ 1}}{0^{ - {\rm{12}}}}\) erg
  • C
    2.2 \( \times {\rm{ 1}}{0^{ - {\rm{12}}}}\) erg
  • D
    2.4 \( \times {\rm{ 1}}{0^{ - {\rm{12}}}}\) erg
    Correct
12
If maximum velocity with which an electron can be emitted from a photo cell is 3.75\( \times {\rm{1}}{0^{\rm{8}}}{\rm{cm}}{{\rm{s}}^{ - {\rm{1}}}}\), then stopping potential is
  • A
    60 volts
  • B
    30 volts
  • C
    40 volts
    Correct
  • D
    50 volts
13
Wavelength of light incident on a photo cell is 3000 \(\mathop A\limits^0 \), if stopping potential is 2.5 volts, then work function of the cathode of photo cell is
  • A
    1.56 eV
  • B
    1.52 eV
  • C
    1.64 eV
    Correct
  • D
    1.41 eV
14
If the frequency of incident light on a certain metal is 8.2 \( \times {\rm{1}}{0^{{\rm{14}}}}\)Hz having threshold frequency of 3.3 \( \times {\rm{1}}{0^{{\rm{14}}}}\) Hz , then cut off potential is
  • A
    3.0 V
    Correct
  • B
    5.1 V
  • C
    4.0 V
  • D
    2.1 V
15
If light of frequency \({\rm{1}}{0^{{\rm{15}}}}\) Hz is incident on sodium having work function 2.5eV,then energy of emitted photoelectrons is
  • A
    2.1 \( \times {\rm{ 1}}{0^{ - {\rm{19}}}}\) J
  • B
    1.6 \( \times {\rm{ 1}}{0^{ - {\rm{19}}}}\) J
  • C
    2.6 \( \times {\rm{ 1}}{0^{ - {\rm{19}}}}\) J
    Correct
  • D
    3.0 \( \times {\rm{ 1}}{0^{ - {\rm{19}}}}\) J