51. Nuclear decay is a
Answer: D. spontaneous and random process
Physics Class 10 Unit 21: Nuclear Physics MCQs
107 multiple choice questions with the correct answer for each. Tap an option to check yourself, or switch on "Show all answers". This is page 2 of 3.
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52. The half-life is the time in which half of the original radioactive nuclei
Answer: B. decay
53. The half-life of a radioactive isotope depends on
Answer: D. the nature of the nucleus only
54. A radioactive element has a half-life of two years. After six years, the sample remaining is
Answer: B. 12.5 %
55. The half-life of a stable isotope is theoretically
Answer: C. infinite
56. A 50 mg sample of lead-212 (half-life 10.6 h) is left for 53 h. The amount left is
Answer: A. 1.56 mg
57. A radioactive substance has a half-life of 16 months. One-eighth of it is left after
Answer: D. 48 months
58. In 420 days one-eighth of polonium remains undecayed. Its half-life is
Answer: A. 140 days
59. The half-life of radium is 1600 years. Starting with 1 kg, 250 g remains after
Answer: B. 3200 years
60. Three-fourth of a radioactive isotope decays in one hour. Its half-life is
Answer: C. 30 minutes
61. The half-life of an isotope is 5 days. Starting with 64,000 nuclei, the number left after 30 days is
Answer: A. 1,000
62. The half-life of carbon-14 is
Answer: D. 5730 years
63. The half-life of uranium-238 is about
Answer: C. 4.5 billion years
64. The SI unit of activity is the
Answer: B. becquerel
65. The curie is equal to
Answer: C. 3.7×1010 decays per second
66. Carbon-14 is formed in the atmosphere when neutrons from cosmic rays collide with
Answer: B. nitrogen atoms
67. After an organism dies, the proportion of carbon-14 in it
Answer: A. gradually decreases
68. Carbon-14 dating is effective for tissues up to about
Answer: D. 50 to 60 thousand years old
69. A fossil has one-eighth of the carbon-14 ratio of a living animal. Its age is (half-life 5730 y)
Answer: B. 17,190 years
70. A skull has 25 % of its initial carbon-14. Its age is
Answer: A. 11,460 years
71. A piece of wood has three tenths of the C-14 of living trees. Its age is about
Answer: C. 9,953 years
72. Ionizing radiation is radiation with energy greater than
Answer: D. 13.6 eV
73. Ionizing radiation mainly damages the cells' molecule called
Answer: A. DNA
74. The most harmful effect of radiation is believed to be the
Answer: B. DNA double-strand break
75. The safety mantra when working around ionizing radiation is
Answer: C. time, distance and shielding
76. The unit of absorbed radiation dose is the
Answer: D. gray
77. The unit of equivalent dose is the
Answer: B. sievert
78. The annual dose limit for the general public is
Answer: C. 1 mSv per year
79. The annual dose limit for radiation workers is
Answer: D. 20 mSv per year
80. The radioactive material in smoke detectors is typically
Answer: A. americium-241
81. A smoke alarm uses a source emitting
Answer: D. alpha particles
82. Food irradiation uses
Answer: A. gamma rays
83. The ideal isotope for food irradiation is
Answer: B. Cobalt-60
84. Beta emitters are used to control the thickness of
Answer: C. thin materials
85. Gamma emitters are used to control the thickness of
Answer: D. thick materials
86. The most commonly used radioisotope in medical diagnosis is
Answer: B. technetium-99m
87. Technetium-99m has a half-life of about
Answer: C. six hours
88. For medical diagnosis, a radioisotope should emit gamma rays and have a
Answer: A. short half-life
89. Iodine-131 is used to treat cancer of the
Answer: B. thyroid gland
90. The largest contributor to natural background radiation for most people is
Answer: D. radon gas
91. Nuclear fission was discovered in 1938 by
Answer: A. Otto Hahn and Fritz Strassmann
92. Nuclear fission is the splitting of a heavy nucleus by absorbing a
Answer: C. neutron
93. On the average, about ______ neutrons are released per fission.
Answer: D. 2.5
94. The energy released in a single fission event is about
Answer: B. 200 MeV
95. 1 kg of uranium delivers as much energy as about
Answer: C. 3000 tons of coal
96. The energy released in nuclear reactions arises from the
Answer: A. mass defect
97. Einstein's mass-energy relation is
Answer: B. E = mc²
98. A mass of 2 µg converted completely into energy releases
Answer: A. 180 MJ
99. If every neutron emitted in fission causes another fission, the process is called a
Answer: C. chain reaction
100. An uncontrolled fission chain reaction is the principle of the
Answer: D. atomic bomb
About Physics Class 10 Unit 21 MCQs (Federal Board)
These 107 Physics MCQs cover Class 10 Unit 21: Nuclear Physics of the Federal Board (FBISE) SSC-II (Class 10) syllabus. They are SLO-based MCQs as per the new pattern for FBISE exams. Each question has four options and the correct answer is shown, so you can practise for the annual examination and find the topics you still need to revise. The questions are split over 3 pages of 50. You can also read the Nuclear Physics notes for this chapter. Download the Nuclear Physics MCQs as a PDF using the button at the top of this page.