Nuclei MCQ Questions for Class 12 Physics Chapter 13 with Answers

Find here the NCERT chapter-wise Multiple Choice Questions from Class 12 Physics book Chapter 13 Nuclei with Answers Pdf free download. This may assist you to understand and check your knowledge about the chapters. Students also can take a free test of the Multiple Choice Questions of Nuclei. Each question has four options followed by the right answer. These MCQ Questions are selected supported by the newest exam pattern as announced by CBSE.


Q1. In nuclear reactors, the control rods are made of

(i) cadmium
(ii) graphite
(iii) krypton
(iv) plutonium

(i) cadmium


Q2. When the mass of a sample of a radioactive substance decreases, the mean life of the sample:

(i) increases
(ii) decreases
(iii) remain unchanged
(iv) first decreases then increases

(iii) remain unchanged


Q3. A nuclear explosive is designed to deliver 1 MW power in the form of heat energy. If the explosion is designed with nuclear fuel consisting of U235 to run a reactor at this power level for one year, then the amount of fuel needed is (given energy per fission is 200 MeV)

(i) 1 kg
(ii) 0.01 kg
(iii) 3.84 kg
(iv) 0.384 kg

(iv) 0.384 kg


Q4. Particles which can be added to the nucleus of an atom without changing its chemical properties are called

(i) neutrons
(ii) electrons
(iii) protons
(iv) alpha particles

(i) neutrons


Q5. The neutron was discovered by whom?

(i) Marie Curie
(ii) Pierre Curie
(iii) Rutherford
(iv) James Chadwick

(iv) James Chadwick


Q6. The mass of an atomic nucleus is less than the sum of the masses of its constituents. This mass defect is converted into

(i) heat energy
(ii) light energy
(iii) electrical energy
(iv) energy which binds nucleons together

(iv) energy which binds nucleons together


Q7. In nuclear reaction, there is conservation of

(i) mass only
(ii) energy only
(iii) momentum only
(iv) mass, energy and momentum

(iv) mass, energy and momentum


Q8. Chadwick was awarded the Nobel prize in Physics in 1935 for his discovery of:

(i) electron
(ii) proton
(iii) neutron
(iv) None of these

(iii) neutron


Q9. For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is:

(i) 20
(ii) 10
(iii) 30
(iv) 15

(i) 20


Q10. For a nuclear fusion process, suitable nuclei are

(i) any nuclei
(ii) heavy nuclei
(iii) lighter nuclei
(iv) nuclei lying in the middle of periodic table

(iii) lighter nuclei


Q11. When a radioactive substance emits an α-particle, its position in the periodic table is lowered by which of the following?

(i) One place
(ii) Two places
(iii) Three places
(iv) Four places

(ii) Two places


Q12. A nuclei having same number of neutron but different number of protons / atomic number are called

(i) isobars
(ii) isomers
(iii) isotones
(iv) isotopes

(iii) isotones


Q13. Light energy emitted by star is due to

(i) breaking of nuclei
(ii) joining of nuclei
(iii) burning of nuclei
(iv) reflection of solar light

(ii) joining of nuclei


Q14. Alpha particle emitted from a radioactive material are:

(i) Helium nuclei
(ii) Hydrogen nuclei
(iii) Lithium nuclei
(iv) None of the above

(i) Helium nuclei


Q15. A radioactive isotope has a half-life of T years. The time it takes its activity to reduce to 3.125% is

(i) 5 T
(ii) 6.654 T
(iii) 5.645 T
(iv) 6.654 T

(i) 5 T


Q16. Nucleus of an atom whose atomic mass is 24 consists of

(i) 11 electrons, 11 protons and 13 neutrons
(ii) 11 electrons, 13 protons and 11 neutrons
(iii) 11 protons and 13 neutrons
(iv) 11 protons and 13 electrons

(iii) Nucleus does not contain electron.


Q17. If alpha, beta, and gamma rays carry the same momentum, which has the longest wavelength?

(i) Alpha rays
(ii) Beta rays
(iii) Gamma rays
(iv) All have the same wavelength

(iv) All have the same wavelength


Q18. A moderator is used in nuclear reactors in order to

(i) slow down the speed of the nuetrons
(ii) acceleerate the neutrons
(iii) increase the number of neutrons
(iv) decrease the number of neutrons

(iii) increase the number of neutrons


Q19. 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?

(i) 27
(ii) 40
(iii) 56
(iv) 120

(i) 27


Q20. Rutherford is the unit of:

(i) radioactivity
(ii) energy
(iii) photoelectric current
(iv) magnetic field

(i) radioactivity


Q21. A nuclei having same number of neutron but different number of protons / atomic number are called

(i) isobars
(ii) isomers
(iii) isotones
(iv) isotopes

(iii) isotones


Q22. If elements with principal quantum number n > 4 were not allowed in nature, then what will be the number of possible elements?

(i) 60
(ii) 20
(iii) 4
(iv) 64

(i) 60


Q23. Chadwick was awarded the 1935 nobel prize in physics for his discovery of the

(i) electron
(ii) proton
(iii) neutron
(iv) positron

(iii) neutron

Q24. The half life of a radioactive susbtance is 30 days. What is the time taken to disintegrate to 3/4th of its original mass?

(i) 30 days
(ii) 15 days
(iii) 60 days
(iv) 90 days


(iii) 60 days


Q25. According to Yukawa’s theory of nuclear forces, the origin of nuclear force between nucleons is due to the exchange of

(i) mesons
(ii) photons
(iii) electrons
(iv) positrons

(ii) photons


Q26. Which one of the following has the identical property for isotopes?

(i) Physical property
(ii) Chemical property
(iii) Nuclear property
(iv) Thermal property

(ii) Chemical property


Q27. Which is a non-central force?

(i) Electrostatic force
(ii) Nuclear force
(iii) Gravitational force
(iv) Spring force

(ii) Nuclear force


Q28. Nucleus of an atom whose atomic mass is 24 consists of

(i) 11 electrons, 11 protons and 13 neutrons
(ii) 11 electrons, 13 protons and 11 neutrons
(iii) 11 protons and 13 neutrons
(iv) 11 protons and 13 electrons

(iii) 11 protons and 13 neutrons


Q29. An electron emitted in beta radiation originates from

(i) inner orbits of atom
(ii) free electrons existing in the nuclei
(iii) decay of a neutron in a nuclei
(iv) photon escaping from the nucleus

(iii) decay of a neutron in a nuclei


Q30. 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.

(i) 0.53 MeV
(ii) 1.06 MeV
(iii) 2.12 MeV
(iv) zero

(ii) 1.06 MeV


Q31. The number of protons in an atom of atomic number Z and mass number A is

(i) zero
(ii) Z
(iii) A – Z
(iv) A

(ii) Z


Q32. The electron emitted in β – radiation originates from where?

(i) Inner orbits of atoms
(ii) Free electrons existing in nuclei
(iii) The decay of a neutron in nuclei
(iv) Photon escaping from the nucleus

(iii) The decay of a neutron in nuclei


Q33. A nuclei having same number of neutron but different number of protons / atomic number are called

(i) isobars
(ii) isomers
(iii) isotones
(iv) isotopes

(iii) isotones


Q34. 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

(i) α, β, γ
(ii) α, γ, β
(iii) β, γ, α
(iv) γ β, α

(i) α, β, γ


Q35. The ground state energy of Hydrogen atom is -13.6 eV. What is the potential energy of electron in this state?

(i) 0 eV
(ii) -13.6 eV
(iii) 2 eV
(iv) -27.2 eV

(iv) -27.2 eV


Q36. Mass energy equation was propounded by

(i) Newton
(ii) Madam Curie
(iii) C. V. Raman
(iv) Einstein

(iv) Einstein


Q37. Nuclear forces are

(i) spin dependent and have no non-central part
(ii) spin dependent and have a non-central part
(iii) spin independent and have no non-central part
(iv) spin independent and have a non-central part

(ii) spin dependent and have a non-central part


Q38. If radio active nuclei emits β-particle, then mass-number:

(i) increased by 1 unit
(ii) decreases by 1 unit
(iii) increases by 2 unit
(iv) decreases by 2 unit

(i) increased by 1 unit


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Class 12 Physics MCQ Questions with Answers

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