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Free download in PDF Class 12 Physics Chapter 13 Nuclei Multiple Choice Questions and Answers for Board, JEE, NEET, AIIMS, JIPMER, IIT-JEE, AIEE and other competitive exams. MCQ Questions for Class 12 Physics with Answers were prepared based on the latest exam pattern. These short solved questions or quizzes are provided by Gkseries. These will help the students for preparation of their examination./p>
(1)
The Bohr model of atoms
[A]
assumes that the angular momentum of elec-trons is quantized.
[B]
uses Einstein’s photoelectric equation.
[C]
predicts continuous emission spectra for at-oms.
[D]
predicts the same emission spectra for all types of atoms.
Answer: assumes that the angular momentum of elec-trons is quantized.
(2)
According to Yukawa’s theory of nuclear forces, the origin of nuclear force between nucleons is due to the exchange of
[A]
mesons
[B]
photons
[C]
electrons
[D]
positrons
(3)
During negative β-decay, an antineutrino is also emitted along with the emitted electron. Then,
[A]
only linear momentum will be conserved
[B]
total linear momentum and total angular momentum but not total energy will be conserved
[C]
total linear momentum, and total energy but not total angular momentum will conserved
[D]
total linear momentum, total angular momentum and total energy will be conserved
Answer: total linear momentum, total angular momentum and total energy will be conserved
(4)
Consider α and β particles and γ-rays each having an energy of 0.5 MeV. In the increasing order of penetrating power, the radiation are respectively
[A]
α, β, γ
[B]
α, γ, β
[C]
β, γ, α
[D]
γ β, α
(5)
The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter is an
[A]
isomer of parent
[B]
isotone of parent
[C]
isotope of parent
[D]
isobar of parent
Answer: isotope of parent
(6)
The radius of a spherical nucleus as measured by electron scattering is 3.6 fm. What is the mass number of the nucleus most likely to be?
[A]
27
[B]
40
[C]
56
[D]
120
(7)
In nuclear reactors, the control rods are made of
[A]
cadmium
[B]
graphite
[C]
krypton
[D]
plutonium
(8)
The half life of a radioactive susbtance is 30 days. What is the time taken to disintegrate to 3/4th of its original mass?
[A]
30 days
[B]
15 days
[C]
60 days
[D]
90 days
(9)
Order of magnitude of density of uranium nucleus is
[A]
1020 kg m-3
[B]
1017 kg m-3
[C]
1014 kg m-3
[D]
1011 kg m-3
(10)
An electron emitted in beta radiation originates from
[A]
inner orbits of atom
[B]
free electrons existing in the nuclei
[C]
decay of a neutron in a nuclei
[D]
photon escaping from the nucleus
Answer: decay of a neutron in a nuclei
(11)
The mass number of iron nucleus is 56 the nuclear density is
[A]
2.29 × 1016 kg m-3
[B]
2.29 × 1017 kg m-3
[C]
2.29 × 1018 kg m-3
[D]
2.29 × 1015 kg m-3
Answer: 2.29 × 1017 kg m-3
(12)
The equation 41 1H+ → 24He2+ + 2e– + 26 MeV represents
[A]
β-decay
[B]
γ-decay
[C]
fusion
[D]
fission
(13)
An element A decays into an element C by a two step process A → B+ 2He4 and B → C + 2e–. Then,
[A]
A and C are isotopes
[B]
A and C are isobars
[C]
B and C are isotopes
[D]
A and B are isobars
Answer: A and C are isotopes
(14)
Complete the series 6He → e– + 6Li +
[A]
neutrino
[B]
antineutrino
[C]
proton
[D]
neutron
(15)
Light energy emitted by star is due to
[A]
breaking of nuclei
[B]
joining of nuclei
[C]
burning of nuclei
[D]
reflection of solar light
Answer: joining of nuclei
(16)
In nuclear reaction, there is conservation of
[A]
mass only
[B]
energy only
[C]
momentum only
[D]
mass, energy and momentum
Answer: mass, energy and momentum
(17)
Alpha particle emitted from a radioactive material are:
[A]
Helium nuclei
[B]
Hydrogen nuclei
[C]
Lithium nuclei
[D]
None of the above
(18)
An electron and a positron each having a mass equivalent to 0.53 MeV annihilate each other and produce a photon. The minimum energy of the photon is.
[A]
0.53 MeV
[B]
1.06 MeV
[C]
2.12 MeV
[D]
zero
(19)
Rutherford is the unit of:
[A]
radioactivity
[B]
energy
[C]
photoelectric current
[D]
magnetic field
(20)
When the mass of a sample of a radioactive substance decreases, the mean life of the sample:
[A]
increases
[B]
decreases
[C]
remain unchanged
[D]
first decreases then increases
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