[140] Important Short Questions Collection of Physics for class 12 NEB

Score 90% in Your Class 12 Physics Exam with These VVIP 2-Mark Questions

1. The angular velocity of the earth around the sun increases when it comes closer to the sun. Why?
2. If the earth were to shrink suddenly what would happen to the length of the day.
3. What do you mean by moment of inertia?
4. State the principle of conservation of angular momentum.
5. Can you distinguish between a raw egg and a hard-boiled egg by spinning each on the table explain.
6. A ballet dancer stretches her hands when she wants to come to rest why?
7. Why it is easier to open the cap of the pen with two fingers than with one finger?
8. Will two spheres of equal mass; one solid and other hollow has an equal moment of inertia? Explain.
9. Explain why spokes are Fitted in the cycle wheel.
10. A pendulum clock is taken to the moon; will it gain or loss time. Why?
11. A simple harmonic motion is represented in usual motion by y=rsin(wt +ϕ),find its acceleration.
12. Define Second's Pendulum.
13. On what factors does the period of a simple pendulum depend.
14. Explain why soldiers are ordered to break steps while crossing the bridge.
15. Why do we say that the velocity and acceleration of a body executing SHM are out phases?
16. What do you mean by damping? What is its cause?
17. At what temperature the surface tension of a liquid is zero?
18. Why do clouds seem to be floating in the sky.
19. Why is the bottom of a ship made heavy explain?
20. The purity of the gold can be tested by weighing it in year in water, how?
21. Why is it easier to lift a body in a liquid than in air?
22. Define Surface tension.
23. Why does hot soup taste better than cold soup.
24. Explain why liquid drops are spherical in shape? Explain.
25. What factors does the circuit tension of a liquid depend on, explain.
26. Antiseptic used in cuts and wounds of human flesh have low surface tension, why?
27. State stokes law.
28. State Bernoulli's theorem.
29. Small air bubbles rise slowly while big bubbles rise rapidly through the liquid. why?
30. Define viscosity. Does it depend on temperature?
31. During certain windstorms, light roofs are blown off. Why?
32. Define Reynold's number?
33. When a smooth flowing stream of water comes out of a faucet, it narrows as it falls. Explain.
34. Why does the temperature of a gas undergo adiabatic expansion decrease?
35. Why does a gas have two specific heat capacities?
36. Is C_p always greater than C_v?
37. What are the limitations of the first law of thermodynamics.
38. Why does a refrigerator consume more power in summer than in winter to cool the same quantity of food by the same degree?
39. Can a room be cooled leaving the doors of electric refrigerator open in a closed room? Explain.
40. Explain the significance of the second law of thermodynamics.
41. Petrol engines are less effective than diesel engines. Explain why?
42. Explain why the temperature of the gas drops in the adiabatic process?
43. State second law of thermodynamics.
44. Can longitudinal waves be polarized? Explain.
45. Distinguish between progressive waves and stationery waves.
46. Frequency is the most fundamental property of a wave. Why?
47. Which types of waves propagate in the liquid, Explain.
48. The speed of sound in humid air is more than that in dry air, why?
49. Define an organ pipe.
50. When we start filling an empty bucket with water, the pitch of sound produced goes on changing. Why?
51. Bells are made of metal but not wood. Why?
52. 
    
53. Why is sounding board used in a string instrument? 54. When the tension in a given stretched string is increased by four times, by what factor does the velocity of transverse wave in the string change?
54. What do you mean by resonance?
55. Why is an end correction necessary for an organ pipe?
56. State Doppler's effect.
57. How is it that one can recognize a friend from his voice without seeing him?
58. Justify the proverb "An empty vessel makes much noise".
59. Why are longitudinal waves called pressure waves.
60. Define beats and beat frequency.
61. Differentiate between a plane wave front and a spherical wave front.
62. What is meant by wave front and wavelets?
63. What is Huygens's principle?
64. The width of fringes obtained in a double slit experiment is 4mm. If one slit is closed, what will happen to the interference fringes?
65. What happens on the interference fringes in a young's double slit experiment when i) the screen is moved away. ii) the source is replaced by another source of shorter wavelength.
66. What are the conditions for destructive and constructive interference of light waves.
67. Distinguish between interference and diffraction.
68. What is the diffraction of light?
69. Does polarizing angle depend on wavelength of light.
70. Can sound waves be polarized? Justify your answer.
71. Differentiate unpolarized and polarized light.
72. Does polarizing angle depend on wavelength of light?
73. What is the principle of potentiometer?
74. Is polarization possible in longitudinal waves? why?
75. State the principle of potentiometer and write down its one application.
76. Why do we prefer a potentiometer with longer wire.
77. Why do we prefer a potentiometer to measure the emf of a cell rather than a voltmeter?
78. A voltmeter has high resistance, explain, why?
79. State and explain Kirchhoff's law of electric circuits.
80. The resistance of an ammeter must essentially be very small, why?
81. What is thermoelectric effect?
82. Does the thermoelectric effect obey the law of conservation of energy? Justify.
83. What is the temperature of inversion? On what factors does it depend.
84. What is neutral temperature? On what factors does it depend?
85. What is thermopile?
86. What is the better representation of the Lorentz force?
87. State Fleming Left hand rule.
88. Why are the pole pieces of magnets cut into cylindrical form in a galvanometer.
89. What do you mean by hall effect? Why is it more effective in semiconductors.
90. Define one ampere in terms of the force between current carrying conductors.
91. State ampere's theorem.
92. What is Curie temperature?
93. Distinguish between diamagnetic and paramagnetic substances in terms of their relative permeability and susceptibility.
94. What is the significance of the area of a hysteresis loop.
95. Permanent magnets are made of steel, why?
96. What is retentivity in coercivity of a ferromagnetic material?
97. Above Curie temperature a ferromagnetic material became para magnetic, why?
98. Define Eddy Current.
99. Define magnetic flux.
100. State Faraday's law of electromagnetic induction.
101. A bar magnet falls through copper ring. Will its acceleration be equal to g? Justify.
102. Bird sitting on a high-tension line wire flying up when current is switched on, why?
103. Lenz law closes the principle of conservation of energy. Explain.
104. Does Lenz law vioate principle of conservation of energy, explain.
105. 220-volt AC is more danger than 220-volt DC, why?
106. Why is choke coil preferred over resistance in AC?
107. Define rms values of alternating current.
108. Define quality factor of resonance in a series LCR circuit.
109. Explain why two parallel wires carrying current in the opposite direction repel each other?
110. Can a uniform magnetic field be used to speed up a charged particle? Explain.
111. Can a hole be created in a metal? Justify your answer.
112. At high frequencies, a capacitor becomes a short circuit, and an inductor becomes an open circuit explain.
113. What is meant by watt-less current.
114. What path does the electron follow in electric field when the electron is projected normally in the field?
115. What property of the cathode rays indicates that they consist of electrons?
116. Cathode rays cannot be regarded as electromagnetic waves, why?
117. Lightening takes place at a higher altitude than at a lower altitude. Why?
118. Can photoelectric effect be explained on the basis of wav theory of light? justify your answer.
119. What happens to the kinetic energy of photo electrons when intensity of light is doubled?
120. What is meant by stopping potential?
121. What is the threshold frequency?
122. What are logic gates? Give a two-truth table for a two input NOR gate.
123. What is truth table? Write down the truth table for a two input NAND gate.
124. Why is x-ray radiation process called inverse photoelectric effect?
125. A proton and an electron have the same de-Broglie wavelength. which one has greater kinetic energy explain
126. The wave nature of particle is not observable in daily life, why?
127. What do you mean by matter waves?
128. What do you mean by uncertainty principle?
129. Point out the importance of de-Broglie wave.
130. State Bohr’s postulate of atomic model.
131. If a radioactive nucleus Has a half-life of one year, will it be completely decayed at the end of two years explain.
132. How does a daughter nucleus differ from its parent
133. Nucleus when it emits i) an alpha particles ii) gamma rays
134. Nucleuses contain no electrons, yet it ejects them explain.
135. There are no electrons inside the nucleus, but they are emitted from an unstable nucleus, why?
136. How do Beta particles differ from electrons?
137. Higgs boson gives the complete picture of the universe. Comment on it.
138. What are the uses of radioisotopes?
139. What is the meaning of ionization energy of hydrogen atom is 13.6 eV?