Chapter # 19 The Atomic Nucleus

PHYSICS

CHAPTER # 19 The Atomic Nucleus

1. 2.

3. 4. 5. 6. 7. 8. 9. 11. 12. 13. 14. 15. 16.

17. 18. 19. 20.

The scientist who discovered electron from the study of the nature of cathode rays was: B a) Ernest Rutherford b) Einstein c) J. J. Thompson d) Niles Bohr The nuclear model of the atom was derived partly from experiments involving the scattering of alpha C particles performed by: a) Newton b) Chadwick c) Rutherford d) Einstein Neutrons and Protons in the nucleus are together called: C a) Atomic particles b) Mesons c) Nucleons d) Photons The bulk of the mass of an atom is concentrated in its: D a) Electron shell b) Neutrons c) Protons d) Nucleus Nuclie having the same nuclear charge but different masses are called: A a) Isotopes b) Isotones c) Isomers d) Isobars An atom of an element differ from an atom of one of its isotopes in the number of: B a) Protons in the nucleus b) Neutrons in the nucleus c) Electrons outside the nucleus d) Valence electrons A naturally occurring disintegration involving the emission of high energy electrons is called: B a) Alpha decay b) Beta decay c) Gamma decay d) Sigma decay Beta particles are: C a) Hydrogen nuclei b) Helium nuclei c) Electrons d) Photons A deuteron is: A a) A proton and neutron bound together b) A type of proton c) A type of neutron d) A type of beta particle A particle having the mass of an electron and the charge of a proton is called: D a) Antiproton b) Photons c) Betatron d) Positron Fusion chain reaction are possible in: C a) A nuclear reactor b) A linear acceleration c) Sun and Stars d) All of the above Atomic theory was announced by Dalton in: C a) 1895 b) 1905 c) 1808 d) 1885 The electron was discovered by J. J. Thomson by passing an electric discharge through: C a) A solid b) A liquid c) A gas at low pressure d) A gas at high pressure Charge on an electron was determined by: C a) Ampere b) Maxwell c) Millikan d) Thomson Rutherford bombarded a thin sheet of gold with: C   a) -rays b) -rays c)  -rays d) X-rays Proton was discovered by Rutherford in: D a) 1915 b) 1918 c) 1910 d) 1920 Chadwick discovered neutron by the study of scattering of alpha particles from: C a) Gold foil b) Nitrogen c) Beryllium d) Oxygen Chadwick discovered in 1932: B a) Proton b) Neutron c) Atom d) Photon Neutron was discovered by: D a) Curie b) Roentgen c) Rutherford d) Chadwick

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PHYSICS

CHAPTER # 19 The Atomic Nucleus

21.

22. 23. 24. 25. 26. 27. 28. 29. 31. 32. 33. 34. 35. 37. 38. 39.

40. 42.

Isotopes of an element are atoms whose nuclei have: a) The same atomic number Z but differ in mass A b) The same mass number A but differ in atomic number Z c) The same number of neutrons but different number of protons d) None of the above Charge on neutron is: a) + 1.6  10-19C b) Zero c) - 1.6  10-19C d) 1.2  10-19C A particle having the mass of an electron and the charge of a proton is called a: a) Antiproton b) Positron c) Gamma rays d) Photon The nucleus consists of: a) Protons and neutrons b) Protons and electrons c) Protons only d) Electrons and neutrons Mass of neutron is: a) 1.6  10-31kg b) 1.6  10-27kg -31  c) 9.1 10 kg d) 1.6  10-30kg Mass of protons is: a) 1.6  10-27kg b) 1.6  10-31kg c) 9.1  10-31kg d) 1.6  10-17kg 1 amu is equal to: a) 1.66  10-24kg b) 1.66  10-19kg -34  c) 1.66 10 kg d) 1.66  10-27kg Atoms in an element whose atomic number are the same but have different mass number are called: a) Isobars b) Isotons c) Isotopes d) Isomers The nuclei having the same mass number but different atomic number are called: a) Isotopes b) Isobars c) Isotones d) Isomers A mass spectrograph (Spectrometer) sorts out: a) Molecules b) Atoms c) Elements d) Isotopes The chemical behaviour of an atom is determined by: a) Binding energy b) Number of isotopes c) Atomic number d) Mass number The mass of a positron is equal to the mass of: a) Neutron b) Proton c) Deutron d) Electron Nuclear force is: a) Attractive and long range b) Repulsive and long range c) Attractive and short range d) None of the above The sum of the masses of constituent nucleons as compared to the mass of the resultant nucleus is: a) Smaller b) Greater c) The same d) Sometimes smaller sometimes greater The amount of energy required to break the nucleus is called its: a) Nuclear energy b) Kinetic energy c) Potential energy d) Binding energy The amount of energy equivalent to 1 amu is: a) 9.315 Mev b) 93.15 Mev c) 931.5 Mev d) 2.224 Mev Radioactivity was discovered by: a) H. Becquerel b) Madam Curie c) Rutherford d) Bohr    , and rays are emitted from a radio-active substance: a) Spontaneously b) When it interacts with the other particle c) When it is heated d) When it is exposed to light Curie is a unit of: a) Reluctance b) Binding energy c) Resistivity d) Radioactivity

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A

B B A B A D C B D C D C B D C A A

D

PHYSICS

CHAPTER # 19 The Atomic Nucleus

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45. 46. 47. 48. 49. 50.

52. 53. 54. 55. 56. 57. 58. 59. 60. 61.

62.

B The reciprocal of decay constant (  ) of a radioactive elements is: a) Half life b) Mean life c) Total life d) Curie An alpha particle is emitted from 88Ra226 what is the mass and atomic number of the daughter C nucleus: Mass Number Atomic Number Mass Number Atomic Number a) 224 84 b) 220 80 c) 222 86 d) 226 87  -particles are: B a) Hydrogen nuclei b) Electrons c) Protons d) Photons Gamma rays consist of a stream of: a) Electrons b) Protons c) Photons d) Positrons Alpha particles are: a) Electrons b) Hydrogen nuclei c) Photons d) Helium nuclei The rate of decay (disintegration per unit time) of radioactive substance: a) Is constant b) Decreases exponentially with time c) Varies inversely as time d) Decreases linearly with time The binding energy per nucleon is: a) Greatest for heavy nuclei b) Least for heavy nuclei c) Greatest for light nuclei d) Least for medium weight nuclei A Curie represents a very strong source of: a)  -particle b)  -particle c) Radioactivity d)  -particle

C D B B C

During fission process, a large amount of: B a) Heat energy is released b) Nuclear energy is released c) Electrical energy is released d) Chemical energy is released Controlled fission chain reaction is maintained in a: A a) Nuclear reactor b) Linear accelerator c) Cyclotron d) Stellerator Fission chain reaction is controlled by introducing: B a) Graphite rods b) Cadmium rods c) Iron rods d) Platinum rods The mass of fissionable material required for self-sustaining chain reaction is called the: C a) Atomic mass b) Fermi mass c) Critical mass d) Super critical mass First atomic reactor was introduced by: C a) Rutherford b) Wilson c) Enrico Fermi d) Curie The moderator used in a nuclear reactor is: D a) Aluminium b) Sodium c) Calcium d) Graphite The atomic bomb is an example of: C a) Controlled nuclear fission b) Controlled nuclear fusion c) Uncontrolled nuclear fission d) Uncontrolled nuclear fusion Tick the correct statement: A a) Moderators slow down the neutrons b) Moderators absorb the fast neutrons c) Moderators reflect the fast neutrons d) Moderators bring the neutrons to rest In liquid metal fast breeder reactor, the type of uranium used is: B a) 92U235 b) 92U238 c) 92U234 d) 92U239 The process in which two or more light nuclei combine together to form heavier nuclei with release B of energy is called: a) Fission b) Fusion c) Chain reaction d) Chemical reaction The source of energy in the sun and the stars is mainly due to: B a) Fission reaction b) Fusion reaction c) Chain reaction d) Chemical reaction

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PHYSICS

CHAPTER # 19 The Atomic Nucleus

63. 64.

65. 66.

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68. 69.

70. 71. 72. 74. 75. 76. 77. 78. 81.

82. 83.

Hydrogen bomb is an example of: a) Nuclear fission b) Nuclear fusion c) Chain reaction d) Chemical reaction The example of fusion reaction is: a) The formation of water from oxygen and hydrogen b) The formation of barium and Krypton from uranium c) The formation of helium from hydrogen d) None of the above Materials can be identified by measuring their: a) Hardness b) Density c) Mass d) Half-life Radioactivity: a) is exhibited more by semiconductors in general b) in exhibited more by the elements when they are coupled with other radio-active elements by a convalent bond c) is an atomic property of radioactive elements d) None of these In 1819, J. J. Thomson performed famous experiment relating to the passage of electric current through: a) Solids b) Liquids c) Gases d) None of these The charge on the electron was successfully determined by: a) Bohr in 1908 b) Millikan in 1909 c) Einstein in 1905 d) Dalton in 1908 According to Rutherford atomic model, the positive charge in an atom: a) is concentrated at its centre b) are in the form of positive electrons at some distance from its centre c) is spread uniformly through its volume d) is readily deflected by an alpha particle For an atom having atomic number Z and atomic weight A, the number of neutrons in the nucleus is: a) A – Z b) A + Z c) Z d) A For an atom having atomic number Z and atomic weight A, the charge on the nucleus is: a) A - Z b) A + Z c) Z d) A For an atom having atomic number Z and atomic weight A, the number of electrons in the atom is: a) A - Z b) A + Z c) Z d) A Mass of proton is of the order of: a) 10-31 mg b) 10-27 kg -24 c) 10 g d) All of them Charge on proton is: a) + 1.59  10-9 C b) + 1.59  10-7 C -19  c) - 1.59 10 C d) + 1.59  10-19 C Mass defect per nucleon is called: a) average energy of nucleons b) binding energy of nucleus c) packing fraction of nucleus d) None of these The energy of an electron revolving in the first orbit of hydrogen atom is: a) -15.4 eV b) -3.4eV c) +13.6eV d) -13.6eV A gram mole of any substance contains: a) 6.021  108 atomic nuclei b) 6.022  1016 atomic nuclei 23  c) 6.022 10 atomic nuclei d) 6.022  1021 atomic nuclei The half life of phosphorus -32 is 15 days. A given mass of phosphorus-32 will be reduced to ¼ of its original mass in: a) 60 days b) 30 days c) 45 days d) 90 days What percent of original radioactive atoms left after five half lives? a) 3% b) 5% c) 10% d) 20% Radioactivity is: a) Self-distruptive activity b) spontaneous activity c) exhibited by all elements under proper conditions d) both ‘a’ and ‘b’

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B C

D C

C

B A

A C C D D C D C B

A B

PHYSICS

CHAPTER # 19 The Atomic Nucleus

84. 85.

86.

Gamma rays carry a charge: a) -e b) c) +2e d) Phenomenon of radioactivity is due to disintegration of: a) Nucleus b) c) Proton d)  -particle carries a charge: a) -2ve c) -ve

87. 88. 89. 90. 91. 92.

93. 94. 95. 96. 97.

98.

99. 100. 102.

D +e None of these A Neutron Molecule C

b) +2ve d) +ve

When a radioactive nucleus emits a  -particle, the proton-neutron ratio: a) decreases b) increases c) remains the same d) none of these The reciprocal of decay constant of a radioactive element is called its: a) Half life b) Mean life c) Total life d) None of these Nuclear reactions can be induced in 92U238 with the bombardment of: a) Slow neutron b) Fast neutron c) Photon d) Graviton Electron was discovered by: a) J. J. Thomson b) Einstein c) Rutherford d) Neil Bohr Neutrons were discovered by bombarding alpha particles on: a) Nitrogen b) Gold c) Beryllium d) Helium The phenomenon of spontaneous nuclear transformation accompanied by emission of energy is called: a) Photoelectric effect b) Compton effect c) Radioactivity d) Pair production Proton was discovered by Rutherford by bombarding nitrogen with: a) Alpha particles b) Beta Particles c) Gamma particles d) X-rays An apparatus used to determine the masses of protons, nuclei, ions is: a) Wilson’s cloud chamber b) Geiger counter c) Mass spectrometer d) Slid state detector Which one of the following cannot be used as moderator: a) Graphite b) Heavy water c) Lead d) None of these Which one of the following can be used as neutron arrestor? a) Graphite b) Heavy water c) uranium d) Cadmium Which one of the following isotopes of uranium can undergo fission with bombardment of slow neutron: a) 92U235 b) 92U234 238 c) 92U d) None of these Half life of a given sample of radium is 22 years. The sample will reduce to 25% of its original value after: a) 11 years b) 22 years c) 44 years d) 88 years According to Rutherford the size of the nucleus is of order of: a) 10-15 m b) 10-14 m -13 c) 10 m d) 10-12 m In discovery of nucleus Rutherford bombarded a thin gold foil with fast moving: a) Beta particles b) Gamma particles c) Alpha particles d) X-rays After alpha decay the atomic number of the atom: a) increases by four b) decreases by two c) increases by two d) decreases by four

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B

B B A C C

A C C D A

C

B C C

PHYSICS

CHAPTER # 19 The Atomic Nucleus

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104.

105. 106. 107. 108. 109. 110. 111. 112. 113. 114. 115. 116. 117.

118. 120. 121. 122.

The half-life of radium is 1600 years. What is the fraction of radium sample that would survive after 6400 years? a) 1/2 b) 1/4 c) 1/8 d) 1/16 Electron was discovered by J.J. Thomson by passing an electric discharge through: a) a gas at low pressure b) a liquid c) a solid d) a gas at a pressure higher than atmospheric pressure Neutron was discovered by: a) Chadwick b) Rutherford c) Neil Bohr d) Einstein Electron was discovered in: a) 1895 b) 1891 c) 1885 d) 1808 Radioactivity was discovered by: a) Rutherford b) Henn Becquad c) Einstein d) Rontgen The charge on electron was discovered by Millikan in: a) 1895 b) 1905 c) 1909 d) 1916 Structure of the nucleus was explained by: a) J.J. Thomson b) Bohr c) Millikan d) Rutherford Rutherford discovered proton in: a) 1925 b) 1920 c) 1906 d) 1909 The diameter of an atom is of the order: a) 10-125 m b) 10-11 m -10 c) 10 m d) 10-9 m An atom of an element differs from an atom of one of its isotopes in the number of: a) Neutrons in the nucleus b) Protons in the nucleus c) Electrons outside the nucleus d) Valence electrons Nuclei that have the same charge number but different mass number are called: a) Isotones b) Isomers c) Isotopes d) Isobars One amu is equal to: a) 1.66  10-27 kg b) 1.6  10-19 kg -24 c) 1.66  10 kg d) 1.67  10-31 kg The rate of decay of a radioactive substance: a) decreases exponentially with time b) decreases linearly with time c) increases linearly with time d) increases exponentially with time Different radioactive materials have: a) Same half lives b) Different half lives c) Same mean lives d) Same total lives The half life of a radioactive element is 6 min. If the initial count rate is 824 per min, how long will it take to reach count rate 206: a) 12 min b) 18 min c) 36 min d) 72 min The time required for a radioactive material to decrease in activity by one half is called: a) half time of the material b) Half life of the material c) Disintegration time d) Mean life of material After alpha decay the mass of the nucleus: a) Increases by four b) Decreases by four c) Does not change d) Increases by two Neutrons are: a) Positively charged b) Negatively charged c) Massless d) Neutral Alpha particles are: a) Hydrogen nuclei b) Helium nuclei c) Lithium nuclei d) Beryllium nuclei

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D

A

A B B C D B C A C A A B A

B B D B

PHYSICS

CHAPTER # 19 The Atomic Nucleus

123. 124.

Gamma particles are: a) Photons c) Neutrons Beta particles are: a) Protons c) Photons

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A b) Electrons d) Protons B b) Electrons d) Neutrons

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