General Science (Physics) Practice Questions for all Exams

1. Which mirror is to be used to obtain a parallel beam of light from a small lamp ? – Concave mirror 
2. The focal length of the lens in a photographic camera is 5 cm. What is the power of the lens? – + 20 D 
3. When viewed in white light, why do soap bubbles show colours? – Because of interference 
4. Angular separation between two colours of the spectrum depends upon which thing? – Angle of deviation 
5. Total internal reflection of light is possible when light enters from which thing? – Water to air 
6. Which is used to remove astigmatism for a human eye? – Cylindrical lens 
7. Why does diffusion of light in the atmosphere take place? – Due to dust particles 
8. Which phenomena can not be attributed to the refraction of light? – Redshift 
9. Total internal reflection can take place when light travels from which thing? – Diamond to glass 
10. The refractive index of a given piece of transparent quartz is greatest for which light? – Violet light 

36. Why is In a hydel station the motion produced in turbines? – Due to the flow of water 
37. What is most suitable for the core of an electromagnet? – Soft iron 
38. At a grid sub stations the voltage is stepped up to reduce loss of which thing? – Power 
39. Equal charges are given to two spheres of different radii. What will the potential be? – More on smaller sphere 
40. Two electron beams are travelling parallel to each other. What will be their reactions? – Repel each other 
41. Instrument used to store the electric charge is known by which name? – Capacitor 
42. When an ebonite rod is rubbed with fur, which charge acquired by the fur? – Positive 
43. Conversion of chemical energy into electrical energy occurs in which thing? – Battery 
44. What is the temperature at which a ferromagnetic material becomes paramagnetic? – Curie temperature 
45. A magnetic needle is kept in non uniform magnetic field. What does itexperiences? – A force and a torque 
46. Where will be the Time period in a vibration magnetometer infinite? – At magnetic pole 
47. The north pole of the earth’s magnet is near the geographical which direction? – South 
48. If the current in the core decreases, what will the strength of the magnetic field be? – Decreases 
49. The intensity of a magnetic field is defined as the force experienced by which pole? – Unit north pole 
50. If a material, placed in a magnetic field is thrown out of it, then how is the material? – Diamagnetic 
51. The capacity of a pure capacitor is 1 farad. In D.C. circuit, what will its effective resistance be? – Infinite 
52. If a bar magnet is cut length wise into 3 parts, what will the total number of poles be? – 6 
53. For electroplating a spoon, it is placed in the voltameter at which postion? – The position of cathode 
54. A substance, when inserted between the poles of a magnet, is pushed out, what is it? – Diamagnetic 
55. By inserting a soft iron piece into solenoid, what does the strength of the magnetic field? – Increase 
56. The magnetic induction associated with currents flowing in a hollow copper tube, how will be? – only out side 
57. How is the electric potential at the centre of a charged conductor? – Same as on the surface 
58. What is not the cause of low conductivity of electrolyte? – Ionisation of salt 
59. What is Electric field intensity at a point a hollow charged spherical conductor? – Is zero 
60. Which property is processed by the ferromagnetic substance? – Hysterasis 
61. Which type of cell can be used if a device requires 75 A of current for 15 seconds? – Lead-acid cell 
62. A hydrogen atom is paramagnetic. What is a hydrogen molecule? – Diamagnetic 
63. In nuclear fission, how many percentage of mass is converted into energy? – 0.1% 
64. X210 has half life of 5 day. What is the time taken for seven-eights of sample of X210 to decay? – 15 days 
65. If a U-238 nucleus splits into two identical parts, how will the two nuclei be so produced? – Stable 
66. What is the half-life of a radioactive element which has only 1/32 of its original mass left after a lapse of 60 days? – 12 days 
67. If a proton of mass m is moving with the velocity of light, what will its mass be? – Infinite 
68. What was the fissionable material used in the bomb dropped at Nagasaki (Japan) in the year 1945? – Plutonium 
69. Energy transferred to a person through gamma rays is measured in by which unit? – Roentgens 
70. Which field is used to produce deflection in a television picture tube? – A magnetic fields 
71. The electron emitted in beta radiation originates from where? – Inner orbits of atoms 
72. From which the cathode ray particles originate in a discharge tube? – Cathode 
73. Einstein’s mass energy relation is given by which expression? – E = mc2 
74. Which rays will deflect in electric field? – Cathode rays 
75. What percentage of the original quantity of a radioactive material is left after five half lives approximately? – 3% 
76. What is the important conclusion given by Millikan’s experiment about the charge? – Charge is quantized 
77. What are Alpha rays emitted from a radioactive substance? – Helium nuclear 
78. Which are the Particles that can be added to the nucleus of an atom without changing its chemical properties? – Neutrons 
79. Which particle has similar mass to that of the electron? – Positron 
80. When the speed of electrons increases, then what happens in the value of the specific charge on an electron? – Decreases 
81. The colour of the +ve column in a gas discharge tube depends on which thing? – The gas in the tube 
82. The first explosion of an atomic device in India was carried out in which state? – Rajasthan 
83. Direct conversion of solar energy with the use of photovoltaic cell results in the production of which energy? – Electrical energy 
84. Why is energy is continuously generated in the sun? – Due to nuclear fusion 
85. What is the ratio of specific charges of an á-particle to that of a proton? – 1/2 
85. Long distance short-wave radio broad casting uses which waves? – Ionospheric wave 
86. Which satellite is used in ship-to-shore and shore-to-shore and shore-to-ship communication? – Marisat 
87. Which is electrical circuits used to get smooth de output from a rectified circuit called? – Filter 
88. When the temperature of semiconductor is increased, what will happen in its electrical conductivity? – Increases 
89. With the rise of temperature, what will happen in the specific resistance of semiconductor? – Decreases 
90. The absorption of radio waves by the atmosphere depends on which thing? – Their frequency 
91. Which are the space waves are affected seriously by atmospheric conditions? – UHF 
92. With which can Radio wave of constant amplitude be generated? – Oscillator 
93. What is the electrical circuit used to get smooth DC output from a rectifier circuit called? – Filter 
94. If germanium has to be doped with a donor impurity, how should the foreign atom be? – Pentavalent 
95. In a p-type semiconductor, Which are the majority charge carriers? – Holes 
96. The unidirectional property of a pn-junction is useful for its use as which thing? – Rectifier 
97. Which energy of the electron at absolute zero is called? – Fermi energy 
98. For television broadcasting, what frequency is employed normally? – 30-300 MHz 
99. A zener diode is also a p – n junction diode. It can be used as which regular? – DC voltage regulator 100. Which effect shows particle nature of height? – Photoelectric effect