Practice Test: General Science- 8 - Notes | Study Science & Technology for UPSC CSE - UPSC

Question 51. A liquid rises in a capillary tube when the angle of contact is________ 

Answer: an acute angle

Question 52. The hydraulic brakes used in automobiles is a direct application of________ 

Answer: Pascal’s Law

Question 53. A periscope works by the principle of________ 

Answer: Reflection and refraction

Question 54. Super conductors are those materials which________ 

Answer: looses all electrical resistance when cooled below a certain temperature

Question 55. Bat can fly in the dark because they are guided by______ waves produced by them. 

Answer: utrasonic

Question 56. A solid piece of iron sinks in water but floats in mercury. This is because the________ 

Answer: Density of iron is more than that of water but less than that of mercury

Question 57. A red object, when seen through a thick blue glass, appears________ 

Answer: Black

Question 58. ________ is the cause of weightlessness experienced while orbiting around earth on a spaceship. 

Answer: Zero gravity

Question 59. If two bodies are completely covered with water, they have________ 

Answer: same density

Question 60. In a reactor, Cadmium rods are used for________ 

Answer: Absorbing neutrons

Question 61. Radar is based on the principle that________ 

Answer: Radio waves are reflected by objects

Question 62. For a given velocity of projection, the maximum range of a projectile can be achieved if the angle of projection is________ 

Answer: 45°

Question 63. Detergents dissolved in water help in cleaning clothes by________ 

Answer: reducing the surface tension of water

Question 64. An aeroplane rises because________ 

Answer: the pressure above its wings is less than the pressure below them.

Question 65. An ordinary clock loses time during summer because the length of the pendulum________ 

Answer: increases and therefore the time period increases

Question 66. The apparent weight of a man in a lift is less than his real weight________ 

Answer: when the lift is going down with uniform acceleration

Question 67. Light from the Sun reaches us in nearly________ 

Answer: 8 minutes

Question 68. A boat loaded with rocks floats in the middle of a swimming pool and a man in the boat throws rocks over board in water. The water level of the pool will___

Answer: be lowered

Question 69. A tennis ball will bounce higher on_____than on plains. 

Answer: higher on hills than on plains

Question 70. The leaning tower of Pisa does not fall because______ 

Answer: the vertical li ne through the C.G. of the tower falls within its base.

Question 71. A man carrying a load on his back bends forward because of one of________ 

Answer: To adjust the C.G. of the system such that the vertical line through the C.G. passes within the base.

Question 72. When milk is churned cream gets separated due to__ 

Answer: centrifugal force

Question 73. Production of beats is a result of the phenomenon of__ 

Answer: interference

Question 74. The internal resistance of ____ of the instruments is the highest. 

Answer: Voltmeter

Question 75. Siphon will fail to work if the level of the liquid in the two vessels are at the________height. 

Answer: same

Question 76. The nature of light waves is similar to________rays. 

Answer: gamma

Question 77. If the radius of the earth were to shrink by one per cent, its mass remaining the same, the acceleration due to gravity on earth’s surface would________ 

Answer: increase

Question 78. A dental plate clings to the roof of the mouth because________ 

Answer: force of adhesion increases

Question 79. At absolute zero of temperature the molecular energy is________ 

Answer: minimum but not zero

Question 80. The half life of a substance is 10 days. How much of the substance will be left after 40 days if initial mass is 2 gm________ 

Answer: 0.125 gm.

Question 81. Angstrom is equal to________nanometer. 

Answer: 10¹

Question 82. A cricketer lowers his hand while catching the ball. This saves him from injury because of________ 

Answer: conservation of momentum

Question 83. One litre of cool air weighs heavier than one litre of dry air because of the________ 

Answer: increased number of molecules at high temperature

Question 84. A piece of rock was brought from moon to earth. Then its weight________ 

Answer: alone changed

Question 85. Diamond is harder than graphite because of difference of________

Answer: crystalline structures

Question 86. Four identical kettles with the same amount of water have bases made of brass, copper, steel and aluminium metals of the same thickness. If these kettles are placed on identical flames in an identical manner, water will boil first in the kettle the base of which is made of________ 

Answer: copper

Question 87. The principle underlying a microwave oven is________ 

Answer: microwaves vibrat e the water molecules in food thereby generating heat.

Question 88. ________is a good conductor of heat and electricity. 

Answer: Graphite

Question 89. Why ________is platinum wire used inside very narrow glass rods?

Answer: Platinum and glass have the same linear coefficients of expansion

Question 90. Grass looks green because________ 

Answer: it absorbs all the colours in the spectrum except green

Question 91. Persistence of vision is the principle behind________ 

Answer: cinema 

Question 92. Television signals cannot be received ordinarily beyond a particular distance due to________ 

Answer: curvature of the earth

Question 93. Cones in the retina of eyes (about 6 million) are concerned with________ 

Answer:  colour disc rimination and acute discrimination of detail

Question 94. A fisherman sitting on the bank of a pond trying to spear a fish should aim________ 

Answer: a little below where he sees the fish

Question 95. The comic mirrors seen in amusement parks have reflecting surfaces that are________ 

Answer: irregularly curved

Question 96. The total internal reflection occurs when the angle of incidence is________than the critical angle. 

Answer: greater

Question 97. After rains if the sun is shining brightly in one part of the sky, ________rainbows are observed. 

Answer: Two

Question 98. In cold countries glycerol is added to water in car radiators as it helps to________ 

Answer: lower the freezing point of water

Question 99. You can hear the roar of the sea on holding a sea shell to your ear because________ 

Answer: the effect of multi-reflections of air producing a vibrating sound

Question 100. A tape-recorder’s tape is coated with a________

Answer: ferromagnetic substance powder