Quiznetik

Physics | Set 11

1. On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because

Correct : C. Cohesion of mercury is greater than its adhesion with glass

2. The mass-energy relation is the outcome of –

Correct : D. special theory of relativity

3. Which set of conditions represents the easiest way to liquiify a gas?

Correct : A. Low temperature and high pressure

4. A person can jump higher on the moon's surface than on the earth because –

Correct : B. the acceleration due to gravity in moon is smaller than that on the earth.

5. Rectifiers are used to convert -

Correct : B. Alternating current to Direct current

6. A dynamo is used to convert –

Correct : A. mechanical energy into electrical energy

7. Absolute Zero is defined as –

Correct : A. The temperature at which all molecular motion ceases

8. When a ring of metal is heated what happens to its hole?

Correct : A. expands

9. Red is used as an emergency or danger signal as –

Correct : B. its wavelength is the longest

10. The dynamo converts –

Correct : A. mechanical energy into electrical energy

11. A small drop of oil spreads over water because :

Correct : B. water has a higher surface tension

12. A small gap is left at the joints of rails in a railway track to –

Correct : A. avoid the tracks being distorted due to seasonal temperature variation

13. Which of the following criterion is used for any metal to be used as a cooking material?

Correct : C. Less thermal conductivity

14. Super conductors are substances that –

Correct : A. offer minimum resistance to flow of electric current

15. Cloudy nights are wanner compared nights, because clouds mainly –

Correct : C. Reflect back the heat given by earth

16. Kepler's law of planetary motion states that the square of the time period is proportional to the –

Correct : C. cube of the semi-major axis

17. Spring tides occur when:

Correct : A. the moon, the sun and the earth are in the same line

18. When a ship enters the sea from a river

Correct : A. It rises a little

19. Why are we able to hear short wave broadcasts better than long wave broadcasts?

Correct : A. Short waves are more energetic than long waves

20. In severe winter, in cold countries water pipes burst because –

Correct : A. Water expands on freezing

21. A television channel is characterized by

Correct : A. frequency of transmitted signal

22. Which one of the following not a feature of Indifference Curve?

Correct : D. They are concave to each other

23. Heat energy of an object is -

Correct : B. The total energy of the molecules of the object

24. If a body moves with a constant speed in a circle –

Correct : D. its velocity remains constant

25. A white and smooth surface is –

Correct : B. bad absorber and good reflector of heat

26. It is easier for a man to swim in sea water, than in river water because –

Correct : B. the density of sea water is more than the density of river water

27. In the pressure cooker, cooking is faster because the increase in vapour pressure -

Correct : D. increases the boiling point

28. Kinetic energy depends on –

Correct : D. both mass and velocity of the moving body

29. The apparent weight of a man in a lift is less the real weight when –

Correct : D. the lift is going down with an acceleration

30. The passengers standing in a bus fall in the backward direction when the stationary bus begins to move. Which of the following laws explains this situation?

Correct : A. Newton's First Law of Motion

31. Plants are dried up in winter due to frost because –

Correct : D. There is mechanical loss of tissues and drought condition prevails

32. Radio telescopes are better than optical telescopes because -

Correct : D. All of the above

33. White clothes are cooler than black ones because they –

Correct : B. reflect all the light that reaches them

34. Sound is heard over longer distances on rainy days because –

Correct : B. sound travels faster in moist air

35. A galvanometer can be converted to a voltmeter by connecting –

Correct : B. a high resistance in series

36. Copper wires are generally used for electrical power transmission instead of iron wire because

Correct : C. copper is a better conductor of electricity than iron

37. The natural environment refers to -

Correct : A. The living organisms and non-living objects or factors in an area undisturbed by human activity

38. Rainbows are produced when sunlight

Correct : B. Incident on rain drops hanging in the atmosphere is dispersed after suffering refraction and internal reflection.

39. The information of brilliant colors in a thin soap film is a consequence of the phenomena of -

Correct : D. Multiple reflection and interference

40. Purpose of an optical filter is to –

Correct : D. transmit or absorb light of different colours

41. Why are covalent compounds poor conductors of electricity?

Correct : B. Due to the absence of charged particles.

42. Which of the following is not correct?

Correct : D. Hygrometer measures sound under water.

43. Which one of the following processes is responsible for the glittering of air bubble rising through water?

Correct : C. Total internal reflection of light

44. Railway tracks are banked on curves so that :

Correct : C. necessary centripetal force may be obtained from the horizontal component of the normal reaction due to track.

45. An electron microscope gives higher magnifications than an optical microscope because –

Correct : B. The wavelength of electrons is smaller as compared to the wavelength of visible light

46. Nichrome wire is used in an electric heater because               .

Correct : D. For all of the above reasons

47. Out of the following pairs, which one does not have identical dimension?

Correct : A. Moment of inertia and moment of a force

48. A concave lens always forms –

Correct : B. a virtual image

49. Ondometer is a -

Correct : B. Measuring instrument for frequency of electromagnetic waves

50. Specific gravity is defined as the ratio of –

Correct : A. density of the substance to the density of water

51. Which one of the following is responsible for the working of New-ton's colour disc experiment?

Correct : C. Persistence of vision

52. What are the two kinds of Rotatory motion?

Correct : B. Spin and Orbital motion

53. The first law of thermodynamics is simply the case of –

Correct : D. The law of conservation of energy

54. If you look into a mirror and find that the image (your reflexion) is smaller than you, then the type of the mirror is -

Correct : D. convex mirror

55. In an optical fibre the signal is transmitted –

Correct : C. due to total internal reflection

56. At boiling point of liquids, its :

Correct : C. Timperature remains increases

57. Transformer is a device to convert –

Correct : C. Low voltage A.C. into high voltage A.C.

58. Two stones of unequal masses are thrown vertically up with the same velocity. Which of the following will happen?

Correct : C. Both will reach the same height

59. Why does ice coverfed in sawdust ct melt quickly?

Correct : C. Sawdust is a bad conductor of heat

60. A man standing close to the platform at a railway station experiences a pulling force towards a fast moving train because of

Correct : D. pressure difference due to fast moving air in between

61. We feel cool when we sit near the fan, this is because –

Correct : C. air vapourises the sweat on our body.

62. The average kinetic energy of the molecules of an ideal gas is directly proportional to –

Correct : C. Absolute temperature of the gas

63. When heated from 0°C to 100°C volume of a given mass of water will –

Correct : D. Decrease and then will Increase

64. Clothes keep us warm in winter because they :

Correct : D. prevent the heat of the body from escaping

65. In a refrigerator what produces the cooling?

Correct : D. None of these

66. Microphone is a device which transforms the –

Correct : A. sound signal into current signal

67. Pressure Cooker cooks faster because

Correct : C. higher temperature is attained for cooking

68. What is a compound microscope?

Correct : B. A microscope that has two sets of lenses : an occular lens and an eyepiece.

69. The temperature of boiling water in a steam engine may be high because -

Correct : C. there is high pressure inside the boiler

70. The motion of a body around a circular path is an example of –

Correct : A. Uniform velocity, variable acceleration

71. A gas thermometer is more sensitive than a liquid thermometer because a gas:

Correct : D. does not change state easily

72. Outside of cooking utensils are generally left black from below because –

Correct : D. black surface is a good absorber of heat.

73. X-rays region lies between –

Correct : C. Gamma-rays and ultraviolet region

74. A star appears twinkling in the sky because of –

Correct : C. refraction of light by atmosphere

75. Water pipes in hilly areas often burst on a cold frosty night, because –

Correct : B. Water in the pipes freezes and on freezing water expands, so pipes break

76. A parachute descends slowly whereas a stone dropped from the same height falls rapidly, because–

Correct : C. A parachute has a larger surface area and air resistance is more

77. For body moving with non-uniform velocity and uniform acceleration –

Correct : B. Displacement – Time graph

78. In electronics what comes under tank circuit?

Correct : C. Capacity and inductance

79. In the process of magnetization of a bar

Correct : A. The entire bulk of the bar gets magnetized

80. A photoelectric cell converts –

Correct : D. Light energy to electrical energy

81. The temperature of a body is an indicator of –

Correct : D. The average kinetic energy of the molecules of the body

82. Two stones of different masses are dropped simultaneously from the top of a building –

Correct : C. Both the stones reach the ground at the same time

83. Rainbow is due to -

Correct : D. refraction and reflection of sunlight by water droplets

84. Condensation process refers to :

Correct : D. Conversion of water vapour into its liquid form

85. If a band is played on the moon the sound will -

Correct : D. not be heard at any distance at all from it

86. In a water lifting electric pump, We convert –

Correct : A. Electrical energy into Potential energy

87. An electron microscope gives higher magnification than an optical microscope, because:

Correct : D. the wavelength of electrons is smaller as compared to the wavelength of visible light

88. We always see the same lace of the moon, because –

Correct : C. It takes equal time for revolution around the earth and rotation on its own axis

89. Which of the following laws validates the statement that matter can neither be created nor destroyed?

Correct : C. Law of conservation of mass

90. What is viewed through an electron microscope?

Correct : B. Structure of bacteria and viruses

91. Rain drops fall from great height. Which among the following statements is true regarding it?

Correct : A. they fall with that ultimate velocity, which are different for different droplets

92. Which of the following occurred first?

Correct : C. Guglielmo Marconi sent out the first wireless signals

93. Why does bleeding occur through the nose in high mountainous regions?

Correct : C. The blood pressure of a person increases at high altitudes

94. Pipelines in cold countries often burst in winter, because –

Correct : A. Water freezes and expands in its volume

95. The modulus of rigidity is the ratio of

Correct : C. Shearing stress to shearing strain

96. In heating frozen foods in sealed pouches in microwaves, why do you first poke holes in the pouch?

Correct : A. To prevent the steam pres-sure from bursting open the pouch

97. A sphere rolls down on two inclined planes of different angles but same height, it does so –

Correct : B. with the same speed

98. During hot weather, the fan produces a feeling of comfort. This is because –

Correct : C. our perspiration evaporates rapidly

99. Stars appears to move from east to west because -

Correct : B. the earth rotates from west to east

100. An egg sinks in soft water but floats in a concentrated solution of salt because –

Correct : C. The density of salt solution exceeds the density of eggs