CBSE Class 12 Physics Nuclei MCQs Set 01

Download CBSE MCQs for Class 12 Physics: Chapter 13 Nuclei

Access targeted multiple-choice questions for Chapter 13 Nuclei designed to align with the latest CBSE academic syllabus for Class 12 Physics. These objective practice sets help students evaluate their conceptual understanding and improve exam readiness.

Chapter-wise Objective Questions: Chapter 13 Nuclei

View or download the dedicated Chapter 13 Nuclei MCQ resource below. Practicing these 50 objective questions regularly builds familiarity with standard exam patterns and helps secure higher marks in final Physics evaluations.

Question : The constituents of nucleus are

(a) electrons and protons
(b) protons and neutrons
(c) neutrons and electrons
(d) electrons, protons and neutrons

Answer: B 


Question : The radius of a nucleus is

(a) directly proportional to its mass number
(b) inversely proportional to its atomic weight
(c) directly proportional to the cube root of its mass number
(d) None of these

Answer: C 

 

Question : A nuclei having same number of neutron but different number of protons / atomic number are called

(a) isobars
(b) isomers
(c) isotones
(d) isotopes

Answer: C 

 

Question : When the number of nucleons in nuclei increases, the binding energy per nucleon

(a) increases continuously with mass number
(b) decreases continuously with mass number
(c) remains constant with mass number
(d) first increases and then decreases with increase of mass number

Answer: D 


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

(a) heat energy
(b) light energy
(c) electrical energy
(d) energy which binds nucleons together

Answer: D 

 

Question : Nuclear forces are

(a) spin dependent and have no non-central part
(b) spin dependent and have a non-central part
(c) spin independent and have no non-central part
(d) spin independent and have a non-central part

Answer: D 

 

Question : On an average, the number of neutrons and the energy of a neutron released per fission of a uranium atom are respectively

(a) 2.5 and 2 keV
(b) 3 and l keV
(c) 2.5 and 2 MeV
(d) 2 and 2 keV

Answer: C 



Question : A moderator is used in nuclear reactors in order to

(a) slow down the speed of the nuetrons
(b) acceleerate the neutrons
(c) increase the number of neutrons
(d) decrease the number of neutrons

Answer: C 

 


Question : Fusion reactions take place at high temperature because

(a) atoms are ionised at high temperature
(b) molecules break up at high temperature
(c) nuclei break up at high temperature
(d) kinetic enrgy is high enough to overcome repulsion between nuclei

Answer: D

 

Question : For a nuclear fusion process, suitable nuclei are

(a) any nuclei
(b) heavy nuclei
(c) lighter nuclei
(d) nuclei lying in the middle of periodic table

Answer: C 

 

Question : Chadwick was awarded the 1935 nobel prize in physics for his discovery of the
(a) electron
(b) proton
(c) neutron
(d) positron
Answer: C

Question : The element gold has
(a) 16 isotopes 
(b) 32 isotopes
(c) 96 isotopes 
(d) 173 isotopes
Answer: B
 
Question : The nuclear radius is of the order of
(a) 10–10 m
(b) 10–6 m
(c) 10–15 m
(d) 10–14 m
Answer: D
 
Question : Particles which can be added to the nucleus of an atom without changing its chemical properties are called
(a) neutrons 
(b) electrons
(c) protons 
(d) alpha particles
Answer: A
 
Question : The radius of a nucleus is
(a) directly proportional to its mass number
(b) inversely proportional to its atomic weight
(c) directly proportional to the cube root of its mass number
(d) None of these
Answer: C
 
Question : Nucleus of an atom whose atomic mass is 24 consists of
(a) 11 electrons, 11 protons and 13 neutrons
(b) 11 electrons, 13 protons and 11 neutrons
(c) 11 protons and 13 neutrons
(d) 11 protons and 13 electrons
Answer: C
 
Question : The electrons cannot exist inside the nucleus because
(a) de-Broglie wavelength associated with electron in β -decay is much less than the size of nucleus
(b) de-Broglie wavelength associated with electron in β -decay is much greater than the size of nucleus
(c) de-Broglie wavelength associated with electron in β -decay is equal to the size of nucleus
(d) negative charge cannot exist in the nucleus
Answer: B
 
Question : In ...X... water is circulated though the reactor vessel and transfers energy to steam generator in the ...Y... Here, X and Y refer to
(a) primary loop, secondary loop
(b) reactor core, turbine
(c) secondary loop, primary loop
(d) turbine, reactor core
Answer: A
 
Question : A nuclei having same number of neutron but different number of protons / atomic number are called
(a) isobars 
(b) isomers
(c) isotones 
(d) isotopes
Answer: C
 
Question : Which one of the following has the identical property for isotopes?
(a) Physical property
(b) Chemical property
(c) Nuclear property 
(d) Thermal property
Answer: B
 
Question : The number of protons in an atom of atomic number Z and mass number A is
(a) zero 
(b) Z
(c) A – Z 
(d) A
Answer: B
 
Question : When the number of nucleons in nuclei increases, the binding energy per nucleon
(a) increases continuously with mass number
(b) decreases continuously with mass number
(c) remains constant with mass number
(d) first increases and then decreases with increase of mass number
Answer: D
 
Question : Mp denotes the mass of a proton and Mn that of a neutron.
A given nucleus, of binding energy B, contains Z protons and N neutrons. The mass M(N, Z) of the nucleus is given
by (c is the velocity of light)
(a) M(N, Z) = NMn + ZMp + B/c2
(b) M(N, Z) = NMn + ZMp – Bc2
(c) M(N, Z) = NMn + ZMp + Bc2
(d) M(N, Z) = NMn + ZMp – B/c2
Answer: D
 
Question : Mass energy equation was propounded by
(a) Newton 
(b) Madam Curie
(c) C. V. Raman 
(d) Einstein
Answer: D
 
Question : The mass of an atomic nucleus is less than the sum of the masses of its constituents. This mass defect is converted into
(a) heat energy
(b) light energy
(c) electrical energy
(d) energy which binds nucleons together
Answer: D
 
Question : Which of the following statement is not true regarding Einsteins mass energy relation?
(a) Mass disappears to reappear as energy.
(b) Energy disappears to reappear as mass.
(c) Mass and energy are two different forms of the same entity.
(d) Mass and energy can never be related to each other.
Answer: D
 
Question : The curve of binding energy per nucleon as a function of atomic mass number has a sharp peak for helium nucleus. This implies that helium
(a) can easily be broken up
(b) is very stable
(c) can be used as fissionable meterial
(d) is radioactive
Answer: B
 
Question : Nuclear forces are
(a) spin dependent and have no non-central part
(b) spin dependent and have a non-central part
(c) spin independent and have no non-central part
(d) spin independent and have a non-central part
Answer: B
 
Question : Nuclear forces exists between
(a) neutron - neutron 
(b) proton - proton
(c) neutron - proton 
(d) all of these
Answer: D
 
Question : The antiparticle of electron is
(a) positron 
(b) α-particle
(c) proton 
(d) β-particle
Answer: D
 
Question : Neutron decay in free space is given as follows 0n1 → 1H1 + -1e0 +[] Then the parenthesis [ ] represents a
(a) neutrino 
(b) photon
(c) antineutrino
(d) graviton
Answer: C
 
Question : Radioactivity is
(a) irreversible process
(b) self disintegration process
(c) spontaneous
(d) all of the above
Answer: D
 
Question : γ-rays are deflected by
(a) an electric field but not by a magnetic field
(b) a magnetic field but not by an electric field
(c) both electric and magnetic field
(d) neither by electric field nor by magnetic field
Answer: D
 
Question : Beta rays emitted by a radioactive material are
(a) electromagnetic radiations
(b) the electrons orbiting around the nucleus
(c) charged particles emitted by nucleus
(d) neutral particles
Answer: C
 
Question : Which of the following is not a mode of radioactive decay ?
(a) Positron emission 
(b) Electron capture
(c) Fusion 
(d) Alpha decay
Answer: C
 
Question : The half-life period and the mean life period of a radioactive element are denoted respectively by Th and Tm. Then
(a) Th = Tm 
(b) Th > T m
(c) Th < Tm 
(d) Th ≥ Tm
Answer: C
 
Question : In γ ray emission from a nucleus
(a) only the proton number changes
(b) both the neutron number and the proton number change
(c) there is no change in the proton number and the neutron number
(d) only the neutron number changes
Answer: C
 
Question : Artificial radioactivity was discovered by
(a) Klaproth 
(b) Rontgen
(c) Irene Curie and Joliot 
(d) P. Curie and M. Curie
Answer: C
 
Question : Radioactive samples are stored in lead boxes because it is
(a) heavy 
(b) strong
(c) good absorber 
(d) bad conductor
Answer: C
 
Question : The process of radioactive radiations remains unaffected due to
(a) physical changes
(b) chemical changes
(c) electric or magnetic fields
(d) all of the above
Answer: D
 
Question : A radioactive material undergoes decay by ejecting electrons. The electron ejected in this process is
(a) the electron from the decay of a neutron
(b) the electron present in the nucleus
(c) the resulting from the conversion of γ photon
(d) an orbital electron
Answer: A
 
Question : The same radioactive nucleus may emit
(a) all the three α, β and γ one after another
(b) all the three α, β and γ radiations simultaneously
(c) only α and β simultaneously
(d) only one α, β and γ at a time
Answer: D
 
Question : Which of the following of a radioactive material is a measure of its instability?
(a) Full life 
(b) Mean life
(c) Half life 
(d) None of these
Answer: C
 
Question : The rate of disintegration at a given instant, is directly proportional to the number of atoms present at that instant. This is the statement of
(a) law of radioactive decay
(b) half life
(c) law of radioactive transformation
(d) group displacement law
Answer: A
 
Question : Fusion reactions take place at high temperature because
(a) atoms are ionised at high temperature
(b) molecules break up at high temperature
(c) nuclei break up at high temperature
(d) kinetic enrgy is high enough to overcome repulsion between nuclei
Answer: D
 
Question : Three specimens A, B, C of same radioactive element has activities 1 microcurie, 1 rutherford and 1 becquerel respectively. Which specimen has maximum mass?
(a) A 
(b) B
(c) C 
(d) all have equal masses
Answer: B
 
Question : Charge on an α-particle is
(a) 1.6 × 10–19 C 
(b) 3.2 × 10–19 C
(c) 1.6 × 10–20 C 
(d) 4.8 × 10–19 C
Answer: B
 
Question : If a radioactive element is placed in an evacuated chamber, then the rate of radioactive decay will
(a) decrease 
(b) remains unchanged
(c) increase 
(d) none of these
Answer:B
 
Question : The γ radiations are
(a) electromagnetic radiation with high energy
(b) electromagnetic radiation with low energy
(c) charged particles emitted by the nucleus
(d) electrons orbiting the nucleus
Answer: A
 
Question : Radioactive substance emits
(a) α-rays 
(b) β-rays
(c) γ-rays 
(d) All of the above
Answer: D
 
Question : The 'rad' is the correct unit used to report the measurement of
(a) the ability of a beam of gamma ray photons to produce ions in a target
(b) the energy delivered by radiation to a target
(c) the biological effect of radiation
(d) the rate of decay of a radioactive source
Answer: C
 
Question : One curie is equal to
(a) 3.7 × 1010 disintegration/sec
(b) 3.2 × 108 disintegration/sec
(c) 2.8 × 1010 disintegration/sec
(d) None of these
Answer: A
 
Question : Half life of radioactive element depends upon
(a) amount of element present
(b) temperature
(c) pressure
(d) nature of element
Answer: D
 
Question : For a nuclear fusion process, suitable nuclei are
(a) any nuclei
(b) heavy nuclei
(c) lighter nuclei
(d) nuclei lying in the middle of periodic table
Answer: C
 
Question : Fusion reaction occurs at temperatures of the order of
(a) 103 K 
(b) 107 K 
(c) 10 K 
(d) 104 K
Answer: B
 
Question : Control rods used in nuclear reactors are made of
(a) stainless steel 
(b) graphite
(c) cadmium 
(d) plutonium
Answer: C
 
Question : Boron rods in a nuclear reactor are used to
(a) absorb excess neutrons
(b) absorb alpha particle
(c) slow down the reaction
(d) speed up the reaction
Answer: A
 
Question : A moderator is used in nuclear reactors in order to
(a) slow down the speed of the nuetrons
(b) acceleerate the neutrons
(c) increase the number of neutrons
(d) decrease the number of neutrons
Answer: C

 

Question : If a star can convert all the He nuclei completely into oxygen nuclei. The energy released per oxygen nuclei is [Mass of He nucleus is 4.0026 amu and mass of Oxygen nucleus is 15.9994 amu]
(a) 7.6 MeV   
(b) 56.12 MeV
(c) 10.24 MeV
(d) 23.9 MeV

Answer: C 


Question : If 200 MeV energy is released in the fission of a single U235 nucleus, the number of fissions required per second to produce 1 kilowatt power shall be (Given 1eV = 1.6 × 10–19 J)
(a) 3.125 × 1013
(b) 3.125 × 1014
(c) 3.125 × 1015
(d) 3.125 × 1016

Answer: A

 


Question : A certain mass of Hydrogen is changed to Helium by the process of fusion. The mass defect in fusion reaction is 0.02866 a.m.u. The energy liberated per a.m.u. is (Given : 1 a.m.u = 931 MeV)
(a) 26.7 MeV
(b) 6.675 MeV
(c) 13.35 MeV
(d) 2.67 MeV

Answer: B 

 

Question : Radioactivity is
(a) irreversible process
(b) self disintegration process
(c) spontaneous
(d) all of the above

Answer: D 

 

Question : Beta rays emitted by a radioactive material are
(a) electromagnetic radiations
(b) the electrons orbiting around the nucleus
(c) charged particles emitted by nucleus
(d) neutral particles

Answer: C


Question :  Which of the following is not a mode of a radioactive decay ?
(a) Positron emission
(b) Electron capture
(c) Fusion               
(d) Alpha decay

Answer: C

 

Question : A radioactive material undergoes decay by ejecting electrons. The electron ejected in this process is
(a) the electron from the decay of a neutron
(b) the electron present in the nucleus
(c) the resulting from the conversion of g photon
(d) an orbital electron

Answer: A


Question : The rate of disintegration at a given instant, is directly proportional to the number of atoms present at that instant. This is the statement of
(a) law of radioactive decay
(b) half life
(c) law of radioactive transformation
(d) group displacement law

Answer: A

 

Question : Half life of radioactive element depends upon
(a) amount of element present
(b) temperature
(c) pressure
(d) nature of element

Answer: D

 

Question : A freshly prepared radioactive source of half life 2 hr emits radiation of intensity which is 64 times the permissible safe level. The minimum time after which it would be possible to work safely with this source is
(a) 6 hr
(b) 12 hr
(c) 24 hr
(d) 128 hr

Answer: B

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