Class 12 Nuclei CBSE Questions & Answers

Class 12 · Nuclei

This is Physics Class 12 Nuclei CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
The antiparticle of electron is
  • A
    Positron
    Correct
  • B
    Proton
  • C
    \(\beta \) –particle
  • D
    \(\alpha \) –particle
2
Plutonium decays with half life of 24000 years. If plutonium is stored for 72000 years, the fraction of it that remains is
  • A
    1 /2
  • B
    41282.0
    Correct
  • C
    1 /4
  • D
    1 /3
3
\({{\rm{B}}^{{\rm{21}}0}}\) has a half life of 5 days. The time taken for seven-eighth of a sample to decay is
  • A
    20 days
  • B
    15 days
    Correct
  • C
    10 days
  • D
    3.4 days
4
A radioactive substance has a half life of four months. Three fourths of the substance will decay in
  • A
    8 months
    Correct
  • B
    12 months
  • C
    3 months
  • D
    4 months
5
The half life of radon is 3.8 days. After how many days will only one twentieth of a radon sample be left over?
  • A
    16.45 days
    Correct
  • B
    10.00 days
  • C
    18.01 days
  • D
    15.45 days
6
The percentage of the original quantity of a radioactive material left after five half lives is approximately
  • A
    1\(\% \)
  • B
    3\(\% \)
    Correct
  • C
    5\(\% \)
  • D
    20\(\% \)
7
The half life of radium is 1600 years. The fraction of a sample of radium that would remain undecayed after 6400 years is
  • A
    1/ 4
  • B
    1/ 8
  • C
    41290.0
    Correct
  • D
    1/ 2
8
Nuclear fusion is possible
  • A
    only between heavy nuclei
  • B
    only between light nuclei
    Correct
  • C
    only between nuclei which are stable against \(\beta \) -decay
  • D
    between both light and heavy nuclei
9
When a hydrogen bomb explodes, which of the following is used?
  • A
    both
    Correct
  • B
    fission
  • C
    neither of two
  • D
    fusion
10
If M is the atomic mass, A is the mass number then (M – A)/A is called
  • A
    Fermi energy
  • B
    Mass defect
  • C
    binding energy
  • D
    packing fraction
    Correct
11
Which of the following is the best nuclear fuel
  • A
    Uranium – 236
  • B
    Thorium – 236
  • C
    Neptunium – 239
  • D
    Plutonium – 239
    Correct
12
Of the following materials, the good moderator is
  • A
    Ordinary water
  • B
    Helium
  • C
    Graphite
    Correct
  • D
    Cadmium
13
The mean binding energy per nucleon in the nucleus of an atom is nearly
  • A
    8 KeV
  • B
    8 MeV
    Correct
  • C
    8 GeV
  • D
    8 eV
14
The process of fusion is used in the construction of
  • A
    an ordinary bomb
  • B
    an atom bomb
  • C
    a neutron bomb
  • D
    a hydrogen bomb
    Correct
15
The energy released when 1 a.m.u. of mass is completely converted into energy is
  • A
    1 MeV
  • B
    391 MeV
  • C
    931 MeV
    Correct
  • D
    797 MeV