Radioactivity MCQs With Answer.

 

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1. The neutral atoms of all isotopes of the same element contain the same number of __________.

A. Neutrons only.

B. Electrons

C. Mass numbers

D. Masses

Ans:- B

2. The atomic number is not changed by which type of radioactive decay?

A. Beta

B. Gamma

C. Alpha

D. The atomic number is affected by all forms of radioactive decay

Answer:- B

3. Isotopes of an element have a different number of

A. Proton

B. Neutron

C. Electron

D. atom

Answer :- B

4. Three types of radioactive elements are emitted when unstable nuclei undergo radioactive decay. Which of the following is not one of them

A) Beta

B) Gamma

C) Alpha

D) Delta

Ans:- D

5. A nuclear fission reaction becoming self-sustaining depends on

A) electrons

B) Neutrons

C) Energy

D) Protons

Ans:- B

6. Helium nuclei particles are called

A) Gamma particles

B) Beta particles

C) Alpha particles

D) No particles that are helium nuclei

Ans:- C

7. When two atomic nuclei combine it is called as

A) Chain reaction

B) Nuclear fusion

C) Nuclear decay

D) Nuclear fission

Ans:- B

8. The number of protons or atomic number is reduced to 2 by which form of radioactive decay?

A) Beta-decay

B) Gamma decay

C) Alpha decay

D) None of the above

Ans:- C

9. Which statement is true for all three types of radioactive emission?

A) They are deflected by electric fields

B) They ionize gases

C) They are completely absorbed by a thin aluminum sheet

D) They emit light

Ans:- B

10. A nuclide of the element plutonium 94 Pu 242. What is the number of neutrons in its nucleus?

A) 242

B) 336

C) 148

D) 94

Ans:- C

11. The neutron was discovered by whom?

A) Marie Curie

B) Pierre Curie

C) Rutherford

D) James Chadwick

Ans:- D

12. The magnetic moment of a revolving electron around the nucleus varies with the principal quantum number as which of the following?

A) μ ∝ n

B) μ ∝ (frac {1}{n})

C) μ ∝ n2

D) μ ∝ (frac {1}{n^2})

Ans:- A

13. Which of the following has the highest neutron ratio?

A) 8O16

B) 2He4

C) 26Fe56

D) 92U235

Ans:- D

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

A) One place

B) Two places

C) Three places

D) Four places

Ans:- B

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

A) Alpha rays

B) Beta rays

C) Gamma rays

D) All have the same wavelength

Answer:- D

16. β-rays emitted from radioactive material are known as electromagnetic radiation.

A) True

B) False

Ans:- B

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

A) 60

B) 20

C) 4

D) 64

Ans:- A

18. For uranium nucleus how does its mass vary with volume?

A) m ∝ V

B) m ∝ (frac {1}{V})

C) m ∝ √V

D) m ∝ V2

Ans:- A

19. Which of the following is a correct statement?

A) Beta rays are the same as for cathode rays

B) Gamma rays are high energy neutrons

C) Alpha particles are singly ionized helium atoms

D) Protons and neutrons have the same mass

Ans:- A

20. Which is a non-central force?

A) Electrostatic force

B) Nuclear force

C) Gravitational force

D) Spring force

Ans:- B

21. Which of the following is an essential requirement for initiating the fusion reaction?

A) Critical mass

B) Thermal neutrons

C) High temperature

D) Critical temperature

Ans:- C

22. What is the reaction responsible for the production of light energy from the sun?

A) Fusion

B) Fission

C) Nuclear

D) Emission

Ans:- A

23. What amount of energy is released by deuterium and tritium fusion?

A) 60.6 eV

B) 12.6 eV

C) 17.6 eV

D) 28.33 eV

Ans:- C

24. In a nuclear reaction, there is the conservation of which of the following?

A) Mass only

B) Energy only

C) Momentum only

D) Mass, energy, and momentum

Ans: D

25. Nuclear fission is possible in which of the following cases?

A) Only between light nuclei

B) Only between heavy nuclei

C) Between both light and heavy nuclei

D) Only between nuclei, which are stable against decay

Ans:- A

26. Solar energy is mainly caused due to fission of uranium present in the sun.

A) True

B) False

Ans:- B

27. Which of the following is used as a moderator in a nuclear reactor?

A) Cadmium

B) Plutonium

C) Uranium

D) Heavy water

Ans:- D

28. In nuclear reactors, what are the controlling rods made of?

A) Cadmium

B) Graphite

C) Stainless steel

D) Plutonium

Ans:- A

29. The operation of a nuclear reactor is said to be critical if the multiplication factor (k) has a value of what?

A) 1

B) 0

C) 1.5

D) 2.1

Ans:- A

30. A neutron can cause fission in which of the following?

A) Hydrogen

B) Uranium-235

C) Thorium

D) Uranium-238

Ans:- B

31. The splitting of a nucleus into smaller nuclei is

A) Fusion

B) Fission

C) Half-life

D) gamma -radiation

Ans:- B

32. Name the moderator used in the nuclear reactor?

A) Plutonium

B) Thorium

C) Graphite

D) Beryllium

Ans:- C

33. Which isotope of Uranium has the capacity to sustain the chain reaction?

A) U-230

B) U-235

C) U-245

D) U-225

Ans:- B

34. Which of the following atomic particles have the least mass?

A) Proton

B) Electron

C) Deuteron

D) Neutron

Ans:- B

35. During an atomic explosion, the energy released is due to

A) Conversion of protons to neutrons

B) Conversion of chemical energy into heat energy

C) Conversion of mechanical energy into nuclear energy

D) Conversion of mass into energy

Ans:- D

36. What is the beneficial aspect of nuclear fission?

A) The ability to absorb energy

B) The ability to produce more energy than nuclear fusion

C) The ability to release tremendous amounts of energy

D) There are no beneficial aspects of nuclear fission

Ans:- C

37. When a neutron leaves the nucleus, it’s mass

A) Triples

B) Decreases

C) Increases

D) Stays the same

Ans:- B

38. The element with the least mass per nucleon is

A) Hydrogen

B) Iron

C) Helium

D) Uranium

Ans:- B

39. The release in energy in nuclear fission is consistent with the fact that uranium has

A) More mass per nucleon than either of the two fragments

B) Has more mass per nucleon as the two fragment

C) Has exactly the same mass per nucleon as the two fragments

D) Less mass per nucleon than either of the two fragments

Ans:- A

40. The energy we get in nuclear reaction comes from

A) Energy we put into the reactor

B) The mass of the fuel

C) Water

D) The sun

Ans:- B

41. The half-life of H3 radioisotope is?

A) 12.26 yr

B) 5730 yr

C) 76 min

D) 28.1 yr

Ans:- A

42. Readily fissile isotopes have ___________ half-lives.

A) short

B) long

C) short & long

D) none of the mentioned

Ans:- B

43. The unit superseding Curie as the unit of Radioactivity is?

A) Decibel

B) Hectare

C) Becquerel

D) None of the mentioned

Ans:- C

44. A series of radioactive fissions is called a _____________

A) Fission Row

B) Fission Chain

C) Fission Column

D) None of the mentioned

Ans:- B

45. Beta decay is usually accompanied by?

A) alpha decay

B) beta decay

C) gamma decay

D) gamma radiation

Ans:- D

46. The amount of energy in MW-days produced of each metric tonne of fuel is?

A) fuel ignition

B) fuel burnup

C) fuel Chain

D) fuel Column

Ans:- B

47. The number of newly born neutrons in an uncontrolled fission reaction is?

A) 2

B) 2.5

C) 2.47

D) 2.38

Ans:- C

48. The process of losing speed of newly born neutrons on collision with other freshly produced neutrons & other obstacles in the way is called?

A) Dispersion

B) Diversion

C) Deviation

D) Scattering

Ans:- D

49. In terms of speed, the newly produced neutrons are classed into how many types?

A) 2

B) 3

C) 4

D) 5

Ans:- B
.

50. The velocity of a fast moving neutron is?

A) 2 m/s

B) 2.4 x 1010 m/s

C) 4.4 x 1010 m/s

D) 4.4 x 106 m/s

Ans:- D

51. In which of the following process are Neutrons emitted?

A. Inverse beta Decay

B. Nuclear fission

C. Spontaneous Fission

D. Nuclear fusion

Ans:- B

52. Heavy nuclei must be such that they can be fissioned by neutrons of an energy such substance are called?

A. Fission fragments

B. Fission Neutrons

C. Fission species

D. Fission elements

Ans:- C

53. Why neutrons with lower energy should be capable of causing fission?

A. For faster reaction process

B. For sustained reaction process

C. For Safety purpose

D. In order to not waste the nuclear fuel

Ans:- B

54. What happens when a neutron is absorbed by a nucleus of an atom of U235?

A. Mass number of atom increases

B. One electron is let out

C. U236 isotope is formed

D. Nucleus becomes unstable

Ans:- C

55. Who invented nuclear fission?

A. Rutherford

B. Hans Bethe

C. Otto Hahn

D. Marie Curie

Ans:- C

56. Atoms of different chemical elements that have the same number of nucleons are called as?

A. Isobars

B. Isotones

C. Isomers

D. Isotopes

Ans:- A
.

57. Most of the energy released in fission process is in process of __________

A. Kinetic Energy

B. Thermal Energy

C. Light Energy

D. Heat Energy

Ans:- A
.

58. Combining of two light nuclei of low mass to produce a heavy nucleus is called ___________

A. Nuclear fusion

B. Nuclear fission

C. Spontaneous fission

D. Double beta decay

Ans:- A

59. What type of Reaction takes place in sun?

A. Nuclear fusion

B. Nuclear fission

C. Spontaneous fission

D. Double beta decay

Ans:- A

60. How many number of nuclei of hydrogen fuse in a series of reaction involving other particles that continually appear and disappear?

A. 1

B. 2

C. 3

D. 4

Ans:- D

61. Why is it necessary to accelerate positively charged nuclei to high kinetic energies to cause fusion?

A. To overcome electrical repulsive forces

B. To result in high amount of energy in short period of time

C. To get the isobars and isotopes

D. To get a sustainable reaction

Ans:- A

62. Fusion reactions are called __________

A. Thermonuclear

B. Thermoduric

C. Thermo Uric

D. Compound reactions

Ans:- A

63. Which of the following element is readily available in the ordinary water?

A. Cesium

B. Thorium

C. Deuterium

D. Astatine

Ans:- C

64. How is tritium made from sea water?

A. By bombarding lithium

B. By bonding with carbon

C. By bombarding Beryllium

D. By reacting with oxygen

Ans:- A

65. What is the function of moderators in nuclear reactor?

A) absorb the secondary neutrons

B) slow down the secondary neutrons

C) control the chain reaction

D) none of the mentioned

Ans:- B

67. Which of the following is not used as a nuclear fuel cladding material?

A) Cadmium

B) Zircalloy

C) Ceramics

D) Stainless Steel

Ans:- A

68. Nuclear fuel complex, Hyderabad is engaged in the job of __________

A) processing of uranium ore

B) manufacture of nuclear fuel elements/assemblies

C) treatment of spent fuel

D) none of the mentioned

Ans:- B

69. Which one is different for the neutral atoms of the isotopes of an element?

A) Number of electrons

B) Atomic weight

C) Atomic number

D) Number of Protons

Ans:- B

70. Thorium can be converted into U-233 in a __________ reactor.

A) fast breeder

B) liquid metal reactor

C) curtis reactor

D) none of the mentioned

Ans:- A

71. A moderator ______ the neutrons.

A) accelerates

B) slows down

C) blocks

D) stops

Ans:- B

72. __________ nuclear reactor does not require a heat exchanger to supply steam to power turbine.

A) pressurised water

B) boiling water

C) helium cooled

D) molten sodium cooled

Ans:- B

73. If 4 gm of a radioisotope has a half-life period of 10 days, the half-life of 2 gm of the same istotope will be __________ days.

A) 10

B) 5

C) 20

D) 30

Ans:- A

74. Thermal neutrons which are used to cause the fission of U-235 have energy __________ eV.

A) >1

B) <0.025

C) >200

D) 1-25

Ans:- B

75. Pick out the wrong statement.

A) Positron is heavier than a proton

B) A, β-ray particle is identical with an electron

C) The nucleus of a hydrogen atom is identical with a proton

D) Mass of an electron is about 1/1800th of the lightest nucleus

Ans:- A

76. Specific gravity of uranium and plutonium is about __________

A) 13

B) 9

C) 19

D) 27

Ans:- C

78. Which of the following types of nuclear reactors is most prone to radioactive hazards?

A) Gas cooled reactor

B) Molten Sodium Reactor

C) Boiling water reactor

D) Pressurised water reactor

Ans:- C

79. The velocity of thermal (slow) neutrons triggering nuclear fission reaction (having energy equal to 0.025 eV) is about __________ metres/second.

A) 1100

B) 2200

C) 3300

D) 4400

Ans:- B

80. Radioactive decay is a ________ change.

A) Physical

B) Chemical

C) Nuclear

D) None of the mentioned

Ans:- C

81. Commercial power generation from fusion reactor is not yet possible, because __________

A) it is hard to control fission

B) it is hard to initiate fission

C) it is a non-periodic process

D) none of the mentioned

Ans:- A

82. First experimental observation of nuclear fission was done by __________

A) Rutherford

B) Hahn & Strassman

C) Plane

D) Fermi

Ans:- D

83. Function of control rod in a nuclear reactor is to control __________

A) pressure

B) temperature

C) fuel consumption

D) absorption of neutrons

Ans:- D

84. “Critical mass” is the minimum mass of nuclear fissile material required for the __________

A) sustainment of chain reaction

B) economic power generation

C) power generation on commercial scale

D) none of the mentioned

Ans:- A

85. Which of the following nuclear materials is fissile?

A) U-239

B) U-235

C) U-232

D) Pu-239

Ans:- D

86. Unit of Radioactivity is?

A) Curie

B) Angstrom

C) Fermi

D) Barn

Ans:- A

87. The ratio of neutrons to protons of an element having a mass number and atomic number of 80 and 40 respectively is?

A) 4

B) 3

C) 2

D) 1

Ans:- D

88. Critical energy should be __________ the neutron binding energy of the atom in order to initiate a nuclear fission.

A) less than

B) equal to

C) either more or less

D) more than

Ans:- D

89. Which is the main ore of uranium?

A) cassiterite

B) chalcopyrite

C) pitchblende

D) monazite sand

Ans:- C

90. Nucleus of tritium has how many neutrons?

A) 1

B) 2

C) 3

D) 4

Ans:- B

91. Percentage of natural uranium present in uranium ore found in Jadugoda (Jharkhand) is?

A) 2

B) 1

C) 0.1

D) 12

Ans:- C

92. Coolant present in the primary circuit of a pressurised water reactor is high pressure __________

A) saturated steam

B) superheated steam

C) saturated water

D) sub cooled water

Ans:- C

93. Candu reactor is a __________ nuclear reactor.

A) natural uranium fueled heavy water cooled & moderated

B) highly enriched uranium (85% U-235) fueled

C) homogeneous

D) fast breeder

Ans:- A
.

94. Extraction of uranium from its ore is done using __________ methods.

A) chemical

B) pyrometallurgical

C) electrometallurgical

D) physical benefaction

Ans:- A

95. Atoms of U-238 and U-235 differ in structure by three __________

A) electrons

B) protons

C) neutrons

D) electrons & three protons

Ans:- C

 

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