MCAT ECAT Physics Second Year Chapter 21 Nuclear Physics

MCAT ECAT Physics Second Year Chapter 21 Nuclear Physics Multiple Choice Question (MCQ) Notes

Both Bold and Underlined option is correct

1. The term "dead time" in G.M counter means the time of the order of:

• More than 1 millisecond
• Less than 1 millisecond
• More than 1 micro sec
• None of these

2. In solid state detector, the reverse bias is applied through the two:

• Conducting layers of silver
• Conducting layers of gold
• Conducting layers of aluminium
• Conducting layers of plastic

3. In solid state detector, the energy needed to produce an electron hole pair is about:

• 3 MeV to 4 MeV
• 3 eV to 4 eV
• Both above options
• None of these

4. The phenomenon of nuclear fission is used in the construction of:

• Atomic bombs
• Hydrogen bomb
• Both above options
• None of these

5. In fission reactor, heavy water is used as:

• Heat exchanger
• Coolant
• Moderator
• None of these

6. The Wilson cloud chamber is based on the principle that supper saturated vapours condense more readily on:

• Ions and dust particles
• Dust particles
• Ions
• None of these

7. Wilson cloud chamber is a device used as:

• Path of ionizing particle
• Accelerating positively charged particle
• Accelerating negatively charged particle
• None of these

8. In Wilson Cloud chamber, the Alpha particle leave:

• Thin and discontinuous tracks
• No tracks
• Thick, straight and continuous tracks
• None of these

9. Geiger counter was designed by:

• Mosley
• Michelson
• Geiger and Muller
• Faraday

10. Geiger Muller counter is suitable for:

• Slow counting
• Fast counting
• Both options above
• None of these

11. Specially designed solid state detector can be used to detect:

• Gamma rays
• X rays
• Alpha particles
• Beta particles

12. A solid state detector is basically:

• A p-n-p transistor
• A n-p-n transistor
• A reverse p-n junction
• A forward p-n junction

13. The potential difference between the top and bottom of a cloud chamber is of the order of:

• 290 V
• 400 V
• 1 KV
• None of these

14. The potential difference between anode and cathode in a neon-bromine filled G.M counter is:

• 290 V
• 400 V
• 1 KV
• 2 MV

15. Which one of the following detectors can count fast and operate at low voltage:

• Solid state detector
• G.M counter
• Wilson cloud detector
• None of these

16. In G.M counter, the positive ions take time to reach the cathode is:

• 10(-2) s
• 10(-3) s
• 10(-4) s
• 10(-6) s

17. The capture of a neutron by a nucleus results in the formation of:

• Deutron
• Proton
• Helium
• Radio isotope

18. Atomic mass scale 1u is equal to:

• 1.66 * 10(18) kg
• 1.66 * 10(-19) kg
• 1.66 * 10(-27) kg
• 1.66 * 10(27) kg

19. One joule of energy absorbed per kilogram of a body is:

• Roentgen
• Grey
• Rem
• Curie

20. The total energy transferred to a body by means of radiation is measured in units of:

• Becquerels
• Grey
• Rem
• Roentgen

21. The SI unit of radiation dose is:

• Roentgen
• Curie
• Grey
• Rem

22. The number of fundamental forces present in nature are:

• 3
• 2
• 5
• 4

23. During fusion of hydrogen into helium:

• Energy is released
• Energy is absorbed
• Mass is increased due to energy absorption
• Mass is reduced due to energy released

24. The mass spectrograph of naturally occurring neon, showing:

• 1 isotope
• 2 isotope
• 3 isotope
• 4 isotope

25. X rays and γ rays of the same energy may be distinguished by:

• their velocity
• their ionizing power
• their intensity
• method of production

26. Which of the following is not  a mode of radioactive?

• Electron emission
• Alpha decay
• Proton emission
• Ionized hydrogen atom

27. The wavelength of γ rays ( in meter is of the order of):

• 10(-7)
• 10(-10
• 10(-12)
• 10(-15)

28. After 2 hours (1/16)th of the initial amount of a certain radioactive isotope remains undecayed. The half-life of the isotope is:

• 60 minutes
• 45 minutes
• 30 minutes
• 15 minutes

29. When Uranium 238U92 decays to lead 206Pb82, the number of alpha particles and beta particles emitted are:

• 6 and 6 respectively
• 8 and 8 respectively
• 6 and 8 respectively
• 8 and 6 respectively

30. The unit of radioactivity is:

• Curie
• Rutherford
• Both first and second
• None of these

31. Half life of a radioactive element depends upon:

• Amount of the element present
• Temperature
• Pressure
• None of the above

32. The nuclei 13C6 and 14N7 can be described as:

• Isotones
• Isobars
• Isotopes of carbon
• Isotopes of nitrogen

33. The rate of decay of a radioactive element:

• is constant
• Decreases inversely with time
• Increases directly with time
• Decreases exponentially

34. A radioactive substance has a half life of four months. Three-fourths of the substance will decay in:

• Three months
• Four months
• Eight months
• Twelve months

35. Particles which can be added to the nucleus of an atom without changing its chemical properties are called:

• Neutrons electrons
• Electrons
• Protons
• Alpha particles

36. Nuclear reactions, we have the conversation of:

• Mass
• Energy only
• Momentum only
• Mass, energy and momentum

37. Atoms having equal number of neutrons as well as equal number of protons but with nucleons in different energy states are called:

• Isotopes
• Isobars
• Isotones
• Isomers

38. If the matter in proton is completely converted into energy, it will be about:

• 9310 MeV
• 100.78 MeV
• 931 MeV
• 10078 MeV

39. One atomic mass unit is equal to:

• 1/12 mass of one C atom
• 1/16 mass of O2 molecule
• 1/14 mass of N2 molecule
•  1/9 mass of F2 molecule

40. The mass number of He is 4 that for sulphur is 32. The radius of sulphur nucleus is larger than that of helium by times:

• √8
• 4
• 2
• 8

41. For nuclear forces to be effective, the distance should be:

• 10(-10) m
• 10(-13) m
• 10(-15) m
• 10(-20) m

42. What was the fissionable material used in the bomb dropped at Nagasaki (Japan) in the year 1945?

• Uranium
• Neptunium
• Berkelium
• Plutonium

43. Which of the following uranium atoms undergo fission readily?

• 238U
• 237U
• 236U
• 235U

44. Control rods used in nuclear reactors are made of:

• Stainless steel
• Graphite
• Cadmium
• Plutonium

45. One atomic mass unit is equal to:

• 1.67 * 10(-27) pound mass
• 1.67 * 10(-27) slug
• 1.67 * 10(-27) kg
• 1.67 * 10(-27) g

46. Nuclei having the same nuclear mass but different nuclear charge are called:

• Isotones
• Isomers
• Isobars
• Isotopes

47. One particle having zero mass and zero charge, which is emitted with beta decay, is called:

• Positron
• Electron
• Neutrino
• Neutron

48. The rate of decay (disintegration per unit time) of a radioactive substance:

• is constant
• Decreases exponentially with time
• Varies inversely as time
• Decreases linearly with time

49. The binding energy per nucleon is:

• Greatest for heavy nuclei
• Least for heavy nuclei
• Greatest for light nuclei
• Greatest for medium weight nuclei

50. Controlled fission reactions are maintained in a:

• Cyclotron
• Linear accelerator
• Nuclear reactor
• Stellerator

51. Alpha particle are highly ionizing because of:

• their high charge and low speeds
• their greater mass
• their larger energy
• their constituents

52. A radioactive decay rate of 3.7 * 10(10) disintegrates per second defines the unit of measurement known as the:

• Rutherford
• Rontgen
• Curies
• Becquerel

53. The total energy transferred to a body by means of radiation is measured in units of:

• Rutherfords
• Rontgens
• Curies
• Becquerels

54. Which of the following radiations are suitable for the treatments of flesh just under skin?

• Alpha radiations
• Beta radiations
• Gamma radiations
• X-rays

55. Fraction of decaying atoms per unit time is:

• Decay constant
• Life-time
• Half-life
• None

56. SI unit of radiation dose is:

• Becquerel
• Curie
• Gray
• All

57. Disintegration of nucleus obeys the laws of conservation of:

• Charge only
• Mass only
• Both charge & mass
• None of above

58. The nuclear fission reaction is the practical example of an:

• Exothermic reaction
• Endothermic reaction
• Chemical reaction
• All of above

59. The quantity called absorbed radiation dose 'D' is defined by:

• E / m
• E / C
• m / c
• C / E

60. The γ-rays radiographs are used in:

• Agricultural industry
• Medical industry
• Support industry
• All of above

61. Subatomic particles are divided into:

• Two groups
• Three groups
• Four groups
• Infinite groups

62. The lightest element which exhibits radioactivity is:

• Hydrogen
• Deuteron
• Tritium
• Helium

63. In radioactive element, β-ray emit from:

NucleusOuter orbitInner orbitNone of these

64. Which one of the following statements is true of both α-particles and X-rays?

They cause ionization of the air when they pass through itThey can be detected after passing through a few millimeters of aluminiumThey can be deflected by electric fieldsThey can be deflected be magnetic fields

65. The radiation having maximum penetration power is:

• X-rays
• γ-rays
• α-rays
• Cathode rays

66. Heavy radioactive elements eventually turn into:

• Barium
• Hydrogen
• Lead
• Radium

67. Emission of β-rays in a radioactive decay results in a daughter element showing a:

• Change in mass but not in charge
• Change in charge but not in mass
• Change in both
• Change in neither

68. A radioactive element zXa emits an α-particle and changes into:

• z-2Ya
• zYa-4
• z-2Ya-4
• z+2Ya

69. When a β-particle is emitted from nucleus, the effect on its neutron-proton ratio is:

• Increased
• Decreased
• Remains same
• Increases and then decreases

70. What is curie?

• Measurement of radioactivity
• Measurement of temperature
• Measurement of magnetism
• Measurement of electric field

71. The mother and daughter elements, with the emission of γ-rays, are called:

• Isotopes
• Isobars
• Isomers
• Isodiaphers

72. The average life (T) and the decay constant λof the radioactive nucleus are related as:

• Tλ = 1
• T = 0.693 / λ
• T / λ = 1
• T = c / λ

73. A nucleus with an excess of neutrons may decay radioactively with the emission of:

• A neutron
• A proton
• An electron
• A positron

74. The penetrating power of X-rays increases with:

• Decrease in their velocity
• Increase in their velocity
• Increase in their intensity
• Decrease in their intensity

75. Such type of radiation which can burn human skin is called:

• Far-infrared
• Infrared
• Ultra-violet
• Microwaves

76. Nuclear force is:

• Attractive and long range force
• Repulsive and long range force
• Attractive and short range force
• Repulsive and short range force

77. Mass defect per nucleon is called:

• Binding energy of nucleus
• Packing fraction
• Average energy of nucleus
• Average energy of reaction

78. The binding energy of Deutron is:

• 22.24 MeV
• 2.224 MeV
• 0.224 MeV
• 222.4 MeV

79. The reciprocal of decay constant (λ) of a radioactive element is:

• Half life
• Mean life
• Total life
• Curie

80. The half-life of a radioactive element depends on:

• Temperature
• Pressure
• Nature of element
• Amount of radioactive substance

81. The radioactive decay obeys the law:

• No = N(1 + e(λt))
• N = Noe(λt)
• N = Noe(-λt)
• No = Ne(-λt)

82. Energy liberated when one atom of 235U92 undergoes fission reaction is:

• 140 MeV
• 28 MeV
• 200 MeV
• 60 MeV 

83. The moderator used in a nuclear reactor is:

• Aluminium
• Sodium
• Calcium
• Graphite

84. The range of 7.7 MeV α-particle in air is about:

• 10 cm
• 20 cm
• 17 cm
• 7 cm

85. A 3MeV β-particle can penetrate through an aluminium foil about:

• 65 mm
• 0.65 mm
• 6.5 mm
• 0.065 mm

86. Geiger Muller counter always uses:

• Argon and alcohol
• Bromine mixed with neon
• Different gases at different pressures
• Argon only

87. The maximum safe limit does person working in nuclear power station is:

• 0.1 rem per week
• 4 rem per week
• 5 rem per week
• 3 rem per week

88. The most useful tracer is:

• Iodine-131
• Strontium-90
• Carbon-14
• Cobalt-60

89. One joule of energy absorbed per kilogram of body is:

• Rem
• Roentgens
• Grey
• Becquerel

90. The types of quarks are:

• 2
• 3
• 4
• 6

91. The strong nuclear force acts on the:

• Mesons only
• π-mesons only
• Photons only
• Hadrons only

92. Which one of the following belongs to Leptons group?

• Electrons
• Neutrino
• Muons
• All of them