JEE Physics Nuclei MCQs Set B

Question:

• a) 19 : 81
• b) 44 : 21
• c) 21 : 44
• d) 81 : 19

Answer: 19 : 81

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) a(iii), b(i), c(iv), d(ii)
• b) a(i), b(iv), c(ii), d(iii)
• c) a(iii), b(i), c(ii), d(iv)
• d) None of these

Answer: a(iii), b(i), c(iv), d(ii)

Question:

• a)

  

• b)

  

• c)

  

• d) All have same penetrating power as all have same kinetic energy

Answer:

Question: In proton-proton cycle, four hydrogen atoms combine to release energy

• a) 26.7 MeV
• b) 26.7 KeV
• c) 2.67 KeV
• d) 2.67 MeV

Answer: 26.7 MeV

Question: 37 Rutherford equals

• a) 1 milli bacquerel
• b) 1 milli curie
• c) 1 micro bacquerel
• d) 1 micro curie

Answer: 1 milli bacquerel

Question: Which of these is incorrect about nuclear forces?

• a) Hadrons do not experience strong nuclear force
• b) Nuclear force is not a central force
• c) Nuclear forces are derived from quark-quark interaction
• d) They are independent of charge

Answer:  Hadrons do not experience strong nuclear force

Question:

• a) 6.0 fm
• b) 4.8 fm
• c) 12.0 fm
• d) 9.6 fm

Answer: 6.0 fm

Question: The volume occupied by an atom is greater than the volume of the nucleus by a factor of about

• a) 10¹⁵
• b) 10¹⁴
• c) 10¹⁰
• d) 10¹²

Answer:  10¹⁵

Question: Alpha particles are

• a) Ionized helium atoms
• b) Protons
• c) Positron
• d) Neutrally charged

Answer: Ionized helium atoms

Question: Two nuclei have their mass numbers in the ratio of 1 : 3. The ratio of their nuclear densities would be

• a) 1 : 1
• b) 1 : 3
• c) 3 : 1
• d) (3)^1/3 : 1

Answer:  1 : 1

Question: The mass number of a nucleus is

• a) Sometimes less than and sometimes more than its atomic number
• b) Sometimes equal to its atomic number
• c) Always more than its atomic number
• d) Always less than its atomic number

Answer:  Sometimes less than and sometimes more than its atomic number

Question:

• a) 72
• b) 73
• c) 74
• d) 75

Answer: 72

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: A nucleus ruptures into two nuclear parts, which have their velocity ratio equal to 2 : 1. What will be the ratio of their nuclear size (nuclear radius)?

• a) 1 : 2^1/3
• b) 2^1/3 : 1
• c) 1 : 3^1/2
• d) 3^1/2 : 1

Answer: 1 : 2^1/3

Question: The most penetrating radiation out of the following are

• a)

  

• b)

  

• c)

  

• d) X-rays

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Mass number reduces by 4
• b) Atomic number reduces by 4
• c) Mass number reduces by 6
• d) Mass number reduces by 2

Answer: Mass number reduces by 4

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: Half-lives of two radioactive substances A and B are respectively 20 minutes and 40 minutes. Initially the samples of A and B have equal number of nuclei. After 80 minutes the ratio of remaining numbers of A and B nuclei is

• a) 1 : 4
• b) 4 : 1
• c) 1 : 16
• d) 1 : 1

Answer: 1 : 4

Question: Nuclear-Fission is best explained by

• a) Liquid drop model
• b) Independent particle model of the nucleus
• c) Proton-proton cycle
• d) None of these

Answer: Liquid drop model

Question: Half life of a radioactive element is 12.5 hour and its quantity is 256 gm. After how much time its quantity will remain 1 g?

• a) 100 hrs
• b) 150 hrs
• c) 200 hrs
• d) 50 hrs

Answer: 100 hrs

Question: Energy released in nuclear fission is due to

• a) Total binding energy of fragments is more than the binding energy of parental element
• b) Some mass is converted into charge
• c) Total binding energy of fragments is less than the binding energy of parental element
• d) Total binding energy of fragments is equals to the binding energy of parental element

Answer: Total binding energy of fragments is more than the binding energy of parental element

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Fission of nuclei is possible because the binding energy per nucleon in them

• a) Decreases with mass number at high mass numbers
• b) Increases with mass number at high mass numbers
• c) Decreases with mass number at low mass numbers
• d) Increases with mass number at low mass numbers

Answer: Decreases with mass number at high mass numbers

Question:

• a) Depends on the mass of the parent nucleus
• b) Greater than 1
• c) Equal to 1
• d) Less than 1

Answer: Depends on the mass of the parent nucleus

Question: The half life of radium is about 1600 years. Of 100 g of radium existing now, 25 g will remain unchanged after

• a) 3200 years
• b) 2400 years
• c) 6400 years
• d) 4800 years

Answer: 3200 years

Question: A sample of radioactive element has a mass of 10 g at an instant t = 0. The approximate mass of this element in the sample after two mean lives is

• a) 1.35 g
• b) 2.50 g
• c) 3.70 g
• d) 6.30 g

Answer:  1.35 g

Question: A sample of radioactive element contains 4 x 10¹⁶ active nuclei. Half life of element is 10 days, then number of decayed nuclei after 30 days

• a) 3.5 × 10¹⁶
• b) 3 × 10¹⁶
• c) 1 × 10¹⁶
• d) None of these

Answer: 3.5 × 10¹⁶

Question: Which rays contain (positive) charged particle?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a)

  

• b)

  

• c) Fussion
• d) Fission

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Z protons and (A – Z) neutrons
• b) A protons and (Z – A) neutrons
• c) Z neutrons and (A – Z) protons
• d) Z protons and A neutrons

Answer: Z protons and (A – Z) neutrons

Question:

• a) c – a – b
• b) c + a – b
• c) a + b – c
• d) a + b + c

Answer: c – a – b

Question: The nuclei of which one of the following pairs of nuclei are isotones?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: 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) Isotope of parent
• b) Isobar of parent
• c) Isomer of parent
• d) Isotone of parent

Answer: Isotope of parent

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Two
• b) One
• c) Three
• d) Four

Answer: Two

Question: Q value of a nuclear reaction is positive. The reaction is

• a) Exothermic
• b) Elastic
• c) Endothermic
• d) Both exothermic and endothermic

Answer: Exothermic

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) 40 s
• b) 20 s
• c) 60 s
• d) 80 s

Answer: 40 s

Question:

• a) 50 days
• b) 30 days
• c) 60 days
• d) 15 days

Answer: 50 days

Question:

• a) 40 microgram
• b) 20 microgram
• c) 10 microgram
• d) 1 microgram

Answer: 40 microgram

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) 200 years
• b) 250 years
• c) 150 years
• d) 100 years

Answer: 200 years

Question: Fusion reaction takes place at high temperature because

• a) Kinetic energy is high enough to overcome the coulomb repulsion between nuclei
• b) Atoms get ionised at high temperature
• c) Nuclei break up at high temperature
• d) Molecules break up at high temperature

Answer: Kinetic energy is high enough to overcome the coulomb repulsion between nuclei

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: When two nuclei (with A = 8) join to form a heavier nucleus, the binding energy (B.E.) per nucleon of the heavier nuclei is

• a) More than the B.E. per nucleon of the lighter nuclei
• b) Same as the B.E. per nucleon of the lighter nuclei
• c) Less than the B.E. per nucleon of the lighter nuclei
• d) Double the B.E. per nucleon of the lighter nuclei

Answer: More than the B.E. per nucleon of the lighter nuclei

Question: When helium nuclei bombard beryllium nuclei, then

• a) Neutrons are emitted
• b) Electrons are emitted
• c) Protons are emitted
• d) Protons and neutrons are emitted

Answer: Neutrons are emitted

Question:

• a) 80 second^–1
• b) 625 second^–1
• c) 20 second^–1
• d) 25 second^–1

Answer: 80 second^–1

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: A radioactive substance has 10⁸ nuclei. Its half life is 30 s. The number of nuclei left after 15 s is nearly

• a) 3 × 10⁶
• b) 7 × 10⁷
• c) 5 × 10⁸
• d) 2 × 10⁵

Answer: 3 × 10⁶

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: In a nuclear reaction transforming a nucleus into another with the emission of a positron, the neutron proton ratio

• a) Increases
• b) May decrease or increase
• c) Decreases
• d) Remains same

Answer: Increases

Question:  If a heavy nucleus has N/Z ratio higher than that required for stability, then

• a)

  

• b)

  

• c)

  

• d) It will undergo K electron capture

Answer:

Question:

• a) A given nucleus may decay at t = 0
• b) No nucleus will decay before t = 8 days
• c) No nucleus will decay before t = 4 days
• d) All nuclei will decay before t = 16 days

Answer: A given nucleus may decay at t = 0

Question: Which of the following is used as a moderator in nuclear reactor?

• a) Heavy water
• b) Uranium
• c) Plutonium
• d) Cadmium

Answer: Heavy water

Question: Which of the following are suitable for the fusion process?

• a) Light nuclei
• b) Heavy nuclei
• c) Element must be lying in the middle of the periodic table
• d) Middle elements, which are lying on binding energy curve

Answer: Light nuclei

Question: Solar energy is mainly caused due to

• a) Fusion of protons during synthesis of heavier elements
• b) Gravitational contraction
• c) Fission of uranium present in the Sun
• d) Burning of hydrogen in the oxygen

Answer:  Fusion of protons during synthesis of heavier elements

Question:

• a) 4.20 × 10⁹ years
• b) 8.40 × 10⁹ years
• c) 3.92 × 10⁹ years
• d) 1.96 × 10⁹ years

Answer: 4.20 × 10⁹ years

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Proton
• b) Neutron
• c) Deutron
• d) Electron

Answer: Proton

Question:

• a) The electrons produced as a result of the decay of neutrons inside the nucleus
• b) The electrons produced as a result of collisions between atoms
• c) The electrons orbiting around the nucleus
• d) The electrons present inside the nucleus

Answer: The electrons produced as a result of the decay of neutrons inside the nucleus

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) 28.4 MeV
• b) 0.061 n
• c) 0.0305 erg
• d) 0.0305 J

Answer:  28.4 MeV

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Neutrino
• b) Proton
• c) Anti-neutrino
• d) Neutron

Answer:  Neutrino

Question:

• a) 8 and 6
• b) 6 and 8
• c) 6 and 6
• d) 8 and 8

Answer: 8 and 6