MCQOPTIONS
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MCQOPTIONS
This section includes 145 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
An atom of mass number 15 and atomic number 7 captures an -particle and then emits a proton. The mass number and atomic number of resulting atom will be respectively |
| A. | 14 and 2 |
| B. | 15 and 3 |
| C. | 16 and 4 |
| D. | 18 and 8 |
| Answer» E. | |
| 52. |
In the following nuclear reaction |
| A. | A neutron |
| B. | A neutrino |
| C. | An electron |
| D. | A proton |
| Answer» C. An electron | |
| 53. |
If a U - 238 nucleus splits into two identical parts, the two nuclei so produced will be |
| A. | Radioactive |
| B. | Stable |
| C. | Isotopes |
| D. | Isobars |
| Answer» C. Isotopes | |
| 54. |
The half - life of a radioactive element which has only 1 / 32 of its original mass left after lapse of 60 days us |
| A. | 12 days |
| B. | 32 days |
| C. | 60 days |
| D. | 64 days |
| Answer» B. 32 days | |
| 55. |
In a discharge tube at 0.2 mm of Hg pressure, there is a formation of |
| A. | Crooke's dark space with glow near the electrodes |
| B. | Crooke's dark space |
| C. | Faraday's dark space |
| D. | Both crooke's and faraday's space partially |
| Answer» B. Crooke's dark space | |
| 56. |
The number of electrons in an atom of atomic number Z and mass number A is |
| A. | A |
| B. | Z |
| C. | A-Z |
| D. | none |
| Answer» B. Z | |
| 57. |
Nucleon is a common name for |
| A. | Proton and electron |
| B. | Electron and neutron |
| C. | Neutron only |
| D. | Neutron and proton |
| Answer» E. | |
| 58. |
What was the fissionable material used in the bomb dropped at Nagasaki (Japan) in the year 1945 ? |
| A. | Uranium |
| B. | Plutonium |
| C. | Neptunium |
| D. | None of these |
| Answer» C. Neptunium | |
| 59. |
The most penetrating radiation out of the following is |
| A. | X - rays |
| B. | - rays |
| C. | - rays |
| D. | y - rays |
| Answer» E. | |
| 60. |
Energy transferred to a person through gamma rays is measured in units of |
| A. | Cuaries |
| B. | Rutherfords |
| C. | Roentgens |
| D. | None of these |
| Answer» D. None of these | |
| 61. |
The nuclear |
| A. | Isobars |
| B. | Isotone |
| C. | Isotopes of carbon |
| D. | None of these |
| Answer» C. Isotopes of carbon | |
| 62. |
The percentage of the original quantity of a radioactive material left after half lives is approximatley |
| A. | 1% |
| B. | 3% |
| C. | 5% |
| D. | 20% |
| Answer» C. 5% | |
| 63. |
In the experiments for determination of e / m of electrons by Thomson method electric and magnetic field are |
| A. | Parallel and both are perpendicular to the motion of the electron |
| B. | Both mutually parallel and also parallel to the motion of the electron |
| C. | . |
| D. | Both mutually perpendicular and have no relation with the motion of the electron |
| Answer» D. Both mutually perpendicular and have no relation with the motion of the electron | |
| 64. |
A radioactive substance has a half life of 4 months. Three fourths of the substance will decays in |
| A. | 6 months |
| B. | 8 months |
| C. | 12 months |
| D. | 16 months |
| Answer» C. 12 months | |
| 65. |
In -decay |
| A. | A is unaffected, Z increases by 1 |
| B. | A is unaffected Z decreases by 1 |
| C. | A increases by 1 and Z is unaffected |
| D. | none of the above |
| Answer» B. A is unaffected Z decreases by 1 | |
| 66. |
If a proton of mass m is moving with the velocity of light, its mass will be |
| A. | Unchanged |
| B. | Large but finite |
| C. | Infinite |
| D. | Zero |
| Answer» D. Zero | |
| 67. |
The half-life of radium is 6400 years. The fraction of a sample of radium that would remain undecayed after 6400 years is |
| A. | 1 / 2 |
| B. | 1 / 4 |
| C. | 1 / 8 |
| D. | 1 / 16 |
| Answer» E. | |
| 68. |
Fusion reaction takes place at high temperature because |
| A. | Atoms are lonized at high temperature |
| B. | Molecules break up at high temperature |
| C. | Nuclei break up at high temperature |
| D. | Kinetic energy is high enough to overcome repulsion at high temperature |
| Answer» E. | |
| 69. |
It is possible to understand nuclear fission on the basis of the |
| A. | Meson theory of the nuclear forces |
| B. | Proton - proton cycle |
| C. | Independent particle model of the nucleus |
| D. | Liquid drop model of nucleus |
| Answer» E. | |
| 70. |
One-sixteenth of initial amount of a radioactive substance remains undecayed after two hours. The half-life of the substance is |
| A. | 15 min |
| B. | 45 min |
| C. | 30 min |
| D. | 60 min |
| Answer» D. 60 min | |
| 71. |
The mass of a neutron is nearly same as that of |
| A. | A proton |
| B. | A meson |
| C. | An epsilon |
| D. | An electron |
| Answer» B. A meson | |
| 72. |
In any fission process. The ratio |
| A. | Greater than 1 |
| B. | Equal to 1 |
| C. | Less than 1 |
| D. | Depends on the mass of the parent nucleus |
| Answer» D. Depends on the mass of the parent nucleus | |
| 73. |
Thomson's cathode ray tube experiment demonstrated that |
| A. | Cathode rays are streams of negatively charged ions. |
| B. | All the mass of an atom is essentially in the nucleus |
| C. | The e / m of electrons in much greater than the e / m of proton. |
| D. | The e / m ratio of the cathode ray particle changes when a different gas is placed in the discharge tube |
| Answer» D. The e / m ratio of the cathode ray particle changes when a different gas is placed in the discharge tube | |
| 74. |
When 30 / 15 P decays to become |
| A. | Electron |
| B. | a - particle |
| C. | Neutron |
| D. | Positron |
| Answer» E. | |
| 75. |
A nuclear reactor harnesses nuclear energy by |
| A. | Nuclear fusion |
| B. | Spontaneous fission |
| C. | Uncontrolled chain reaction |
| D. | Controlled chain reaction |
| Answer» E. | |
| 76. |
In the following nuclear reaction, |
| A. | A proton |
| B. | A neutron |
| C. | A neutrino |
| D. | An electron |
| Answer» D. An electron | |
| 77. |
When a triton capture a proton, it becomes |
| A. | Neutron |
| B. | Meson |
| C. | - particle |
| D. | Deuteron |
| Answer» D. Deuteron | |
| 78. |
Consider the following metals |
| A. | 1 and 2 |
| B. | 1, 2 and 3 |
| C. | 2 and 3 |
| D. | 1 and 3 |
| Answer» E. | |
| 79. |
In nuclear fission, the percentage of mass converted into energy is about |
| A. | 10% |
| B. | 0.01% |
| C. | 0.1% |
| D. | 1% |
| Answer» D. 1% | |
| 80. |
A good moderator should |
| A. | Not be a gas only |
| B. | Not have appetite for neutrons only |
| C. | Be light in mass number only |
| D. | Be all above three |
| Answer» E. | |
| 81. |
A strong argument for the particle nature of cathode rays is that they |
| A. | Travel through vacuum |
| B. | Produce fhorescence |
| C. | Cast shadow |
| D. | Get deflected in magnetic field |
| Answer» D. Get deflected in magnetic field | |
| 82. |
Cathode rays are made up of electrons. Anode rays are made up of |
| A. | Protons only |
| B. | Protons and positrons only |
| C. | Positive residence of atom |
| D. | All positive particles of atom |
| Answer» D. All positive particles of atom | |
| 83. |
Consider the following statements in a nuclear reactor, self sustained chain reaction is possible, because |
| A. | 1, 2 and 3 |
| B. | 1 and 3 |
| C. | 2 and 4 |
| D. | 2, 3 and 4 |
| Answer» B. 1 and 3 | |
| 84. |
(e/m) ratio of anode rays produced in discharge tube, depends on the |
| A. | Nature of the gas filled in the tube |
| B. | Nature of the material of anode |
| C. | Nature of the material of cathode |
| D. | All of the aboveq |
| Answer» B. Nature of the material of anode | |
| 85. |
Which of the following particles is unstable ? |
| A. | Proton |
| B. | Electron |
| C. | Photon |
| D. | Neutron |
| Answer» E. | |
| 86. |
Which of the following nuclei undergo fission when struck by thermal neutrons ? |
| A. | 1 and 2 only |
| B. | 2 and 3 only |
| C. | 1 and 3 only |
| D. | 1, 2 and 3 |
| Answer» D. 1, 2 and 3 | |
| 87. |
The electrons are emitted in the photoelectric effect from a metal surface. |
| A. | Only if the frequency of the incident radiation is above a certain threshold value |
| B. | Only if the temperature of the surface is high |
| C. | At the rate of independent of the nature of the metal |
| D. | None of the above |
| Answer» B. Only if the temperature of the surface is high | |
| 88. |
A - particle is emitted by radioactive nucleus at the time of conversion of |
| A. | A nucleon into energy |
| B. | A positron into energy |
| C. | A neutron into a proton |
| D. | A proton into a neutron |
| Answer» D. A proton into a neutron | |
| 89. |
The number of atoms of a radioactive substance at t = 0 is 8 x 10 |
| A. | 9 years |
| B. | 12 years |
| C. | 16 years |
| D. | none |
| Answer» C. 16 years | |
| 90. |
Percentage of the original number of atoms in a radioactive sample remaining at the end of one mean life is |
| A. | 50 |
| B. | 60 |
| C. | 63 |
| D. | 37 |
| Answer» E. | |
| 91. |
Which of the following has rest mass greater than others ? |
| A. | Electron |
| B. | Photon |
| C. | - Meson |
| D. | Positron |
| Answer» D. Positron | |
| 92. |
The scientist who experimentally showed that electric charge is quantised only in terms of integral multiples of electronic charge is |
| A. | Max Born |
| B. | Max planck |
| C. | Thomson |
| D. | Millikan |
| Answer» E. | |
| 93. |
The half - life (T) and the disintegration constant ( ) of the radioactive substance are related as |
| A. | T = 1 |
| B. | T = 0.693 |
| C. | T / = 0.693 |
| D. | / T = 0.693 |
| Answer» C. T / = 0.693 | |
| 94. |
To produce deflection in a television picture tube |
| A. | An electric field is used |
| B. | A magnetic fields is used |
| C. | Both electric and magnetic field are used |
| D. | None of the above |
| Answer» C. Both electric and magnetic field are used | |
| 95. |
The fusion of hydrogen into helium is more likely to take place |
| A. | At high temperature and high pressure |
| B. | At high temperature and low pressure |
| C. | At low pressure and low temperature |
| D. | None of the above |
| Answer» B. At high temperature and low pressure | |
| 96. |
In gamma (y) decay |
| A. | Both A and Z increase by 1 |
| B. | Both A and Z decrease by 1 |
| C. | Neither A nor Z changes |
| D. | A is always equal to Z |
| Answer» D. A is always equal to Z | |
| 97. |
In the photoelectric effect, electrons are emitted |
| A. | At a rate that is independent of the emitter |
| B. | At a rate that is proportional to the square of the amplitude of the incident radiation |
| C. | With a maximum velocity proportional to the frequency of incident radiation |
| D. | Only if the frequency of the incident radiation is above a threshold value |
| Answer» E. | |
| 98. |
Photocells are used for the |
| A. | Reproduction of pictures from the cinema film |
| B. | Reproduction of sound from the cinema film |
| C. | Automatic switching of street light |
| D. | (b) and (c) both |
| Answer» E. | |
| 99. |
Photoelectric effect can be explained by assuming that light |
| A. | Is a form of transverse wave |
| B. | Is a form of longitudinal wave |
| C. | Can be polarised |
| D. | Consists of quanta |
| Answer» E. | |
| 100. |
y-rays are deflected by |
| A. | An electric field but not by a magnetic filed |
| B. | A magnetic field but not by an electric field |
| C. | Both electric and magnetic field |
| D. | Neither electric field nor magnetic field |
| Answer» E. | |