CBSE Class 12 Physics Nuclei MCQs Set C

Question. The formula which gives the wavelength of emitted photon when electron jumps from higher nergy state to lower was given by 
a) Balmer
b) Paschen
c) Lymen
d) Rydberg

Answer: D

Question. What is the kinetic energy of α-particles bombarded towards the gold nucleus in Geiger and Marsden classic experiment? 
a) 8.8×10^-13 Joule
b) 8.8×10^-15 Joule
c) 8.8×10^-13 Joule
d) x 10^-13 Joule

Answer: A

Question. What is the range of volume of hydrogen nucleus?   
a) 10^-45m.
b) 10^-30m.
c) 10^-15m.
d) 10^-60m.

Answer: A

Question. What is true about Bohr’s atomic Model             
a) His model was unique totally different from other
b) His model is a modification of Rutherford atomic model.
c) His model is a modification of Thomson atomic model.
d) None of the above

Answer: B

Question. Relative density of nucleus with respect to water is     
a) 2.3 × 10¹⁷ kgm^–3
b) 2.3 × 10¹⁴ kgm–³
c) 23 × 10¹⁷ kgm^–3
d) .23 × 10¹⁷ kgm^–3

Answer: B

Question. From R = R0 A1/3how can we conclude that density of almost all the nucleus is same       
a) Volume being proportional to square of R density becomes independent of mass number A
b) Volume being proportional to cube of R density becomes independent of mass number A
c) Volume being proportional to R density becomes independent of mass number A
d) Density has no relation with R

Answer: B

Question. Bohr’s atomic model is applicable for         
a) All types of atoms
b) Only for hydrogen atom
c) For hydrogen like atoms
d) For H₂ gas.

Answer: C

Question. The cause of rejection of Rutherford atomic model was     
a) It was totally wrong
b) It could not justify its stability
c) Rutherford was unable to explain it
d) None of the above.

Answer: B

Question: The binding energy per nucleon of ₃⁷Li and ₂⁴He nuclei are 5.60 MeV and 7.06 MeV respectively. In the nuclear reaction₃⁷Li + ₁¹H → ₂⁴He + ₂⁴He +Qthe value of energy Q released is
(a) 19.6 MeV
(b) –2.4 MeV
(c) 8.4 MeV
(d) 17.3 MeV
Answer: d

Question: The half life of a radioactive isotope X is 50 years. It decays to another element Y which is stable. The two elements X and Y were found to be in the ratio of 1 : 15 in a sample of a given rock. The age of the rock was estimated to be
(a) 150 years
(b) 200 years
(c) 250 years
(d) 100 years
Answer: b

Question: Which of the following are suitable for the fusion process?
(a) Light nuclei
(b) Heavy nuclei
(c) Element lying in the middle of the periodic table
(d) Middle elements, which are lying on binding energy curve.
Answer: a

Question: Energy released in nuclear fission is due to
(a) some mass is converted into energy
(b) total binding energy of fragments is more than the binding energy of parental element
(c) total binding energy of fragments is less than the binding energy of parental element
(d) total binding energy of fragments is equal to the binding energy of parental element.
Answer: a

Question: Atomic weight of Boron is 10.81 and it has two isotopes ₅B¹⁰ and ₅B¹¹. Then the ratio of ₅B¹⁰ : ₅B¹¹ in nature would be
(a) 15 : 16
(b) 10 : 11
(c) 19 : 81
(d) 81 : 19 
Answer: c

Question: The nuclei ₆C¹³ and ₇N¹⁴ can be described as
(a) isotones
(b) isobars
(c) isotopes of carbon
(d) isotopes of nitrogen
Answer: a

Question: a-particle consists of
(a) 2 protons only
(b) 2 protons and 2 neutrons only
(c) 2 electrons, 2 protons and 2 neutrons
(d) 2 electrons and 4 protons only
Answer: b

Question: The volume occupied by an atom is greater than the volume of the nucleus by a factor of about
(a) 10¹
(b) 10⁵
(c) 10¹⁰
(d) 10¹⁵
Answer: d

Question:The energy required to break one bond in DNA is 10^–20 J. This value in eV is nearly
(a) 6
(b) 0.6
(c) 0.06
(d) 0.006
Answer: c

Question: The constituents of atomic nuclei are believed to be
(a) neutrons and protons
(b) protons only
(c) electrons and protons
(d) electrons, protons and neutrons
Answer: a

Question: The energy equivalent of 0.5 g of a substance is
(a) 4.5 × 10¹⁶ J
(b) 4.5 × 10¹³ J
(c) 1.5 × 10¹³ J
(d) 0.5 × 10¹³ J
Answer: b

Question: The mass of proton is 1.0073 u and that of neutron is 1.0087 u (u = atomic mass unit). The binding energy of ₂⁴He is
(Given helium nucleus mass ≈ 4.0015 u)
(a) 0.0305 J
(b) 0.0305 erg
(c) 28.4 MeV
(d) 0.061 u
Answer: c

Question:Two nuclei have their mass numbers in the ratio of 1 : 3. The ratio of their nuclear densities would be
(a) (3)^1/3 : 1
(b) 1 : 1
(c) 1 : 3
(d) 3 : 1
Answer: b

Question: The ratio of the radii of the nuclei ₁₃Al²⁷ and ₅₂Te¹²⁵ is approximately
(a) 6 : 10
(b) 13 : 52
(c) 40 : 177
(d) 14 : 73 
Answer: a

Question: How does the Binding Energy per nucleon vary with the increase in the number of nucleons?
(a) Decrease continuously with mass number.
(b) First decreases and then increases with increase in mass number.
(c) First increases and then decreases with increase in mass number.
(d) Increases continuously with mass number.
Answer: c

Question: A nucleus _A^ZX has mass represented by M(A, Z). If M_p and M_n denote the mass of proton and neutron respectively and B.E. the binding energy in MeV, then
(a) B.E. = [ZM_p + (A – Z)M_n – M(A, Z)]c²
(b) B.E. = [ZM_p + AM_n – M(A, Z)]c²
(c) B.E. = M(A, Z) – ZM_p – (A – Z)M_n
(d) B.E. = [M(A, Z) – ZM_p – (A – Z)M_n]c² 
Answer: a

Question: The mass of a ₃⁷Li nucleus is 0.042 u less than the sum of the masses of all its nucleons. The binding energy per nucleon of ₃⁷Li nucleus is nearly
(a) 46 MeV
(b) 5.6 MeV
(c) 3.9 MeV
(d) 23 MeV
Answer: b

Question: A mixture consists of two radioactive materials A₁ and A₂ with half lives of 20 s and 10 s respectively. Initially the mixture has 40 g of A₁ and 160 g of A₂. The amount of the two in the mixture will become equal after
(a) 60 s
(b) 80 s
(c) 20 s
(d) 40 s 
Answer: d

Question: M_n and M_p represent the mass of neutron and proton respectively. An element having mass M has N neutrons and Z protons, then the correct relation will be
(a) M < {N · M_n + Z · M_p}
(b) M > {N · M_n + Z · M_p}
(c) M = {N · M_n + Z · M_p}
(d) M = N {M_n + M_p} 
Answer: a

Question: The half life of radium is about 1600 years. If 100 g of radium existing now, 25 g will remain unchanged after
(a) 4800 years
(b) 6400 years
(c) 2400 years
(d) 3200 years 
Answer: d

Question: The half-life of a radioactive substance is 30 minutes. The time (in minutes) taken between 40% decay and 85% decay of the same radioactive substance is
(a) 15
(b) 30
(c) 45
(d) 60
Answer: d

Question: Fission of nuclei is possible because the binding energy per nucleon in them
(a) increases with mass number at low mass numbers
(b) decreases with mass number at low mass numbers
(c) increases with mass number at high mass numbers
(d) decreases with mass number at high mass numbers.
Answer: d

Question: If the nucleus ₁₃²⁷Al has a nuclear radius of about 3.6 fm, then ₃₂¹²⁵Te would have its radius approximately as
(a) 9.6 fm
(b) 12.0 fm
(c) 4.8 fm
(d) 6.0 fm 
Answer: d

Question: The binding energy per nucleon is maximum in case of
(a) ₂⁴He
(b) ₂₆⁵⁶Fe
(c) ₁₄₁⁵⁶Ba
(d) ₉₂²³⁵U
Answer: b

Question: Which of the following statements is true for nuclear forces?
(a) They obey the inverse square law of distance.
(b) They obey the inverse third power law of distance.
(c) They are short range forces.
(d) They are equal in strength to electromagnetic forces. 
Answer: c

Question: The decay constant of a radio isotope is λ. If A₁ and A₂ are its activities at times t₁ and t₂ respectively, the number of nuclei which have decayed during the time (t₁ – t₂)
(a) A₁t₁ – A₂t₂
(b) A₁ – A₂
(c) (A₁ – A₂)/λ
(d) λ(A₁ – A₂)
Answer: c

Question: The mass density of a nucleus varies with mass number A as
(a) A²
(b) A
(c) constant
(d) 1/A 
Answer: c

Question: In the nucleus of ₁₁Na²³, the number of protons, neutrons and electrons are
(a) 11, 12, 0
(b) 23, 12, 11
(c) 12, 11, 0
(d) 23, 11, 12
Answer: a

Question:The average binding energy of a nucleon inside an atomic nucleus is about
(a) 8 MeV
(b) 8 eV
(c) 8 J
(d) 8 erg
Answer: a

Question: If the nuclear radius of ²⁷Al is 3.6 fermi, the approximate nuclear radius of ⁶⁴Cu in fermi is
(a) 2.4
(b) 1.2
(c) 4.8
(d) 3.6 
Answer: c