# GENERAL SCIENCE – PHYSICS- 81 TO 90

81. Inside an aeroplane, flying at a high altitude,

A.the pressure is the same as that outside
B.normal atmospheric pressure is maintained by the use of air pumps
C.the pressure inside is less than the pressure outside
D.normal humidity and partial vacuum are maintained

Answer: Option B- normal atmospheric pressure is maintained by the use of air pumps

82. Sound travels with a different speed in media. In what order does the velocity of sound increase in these media?

A.Water, iron and air
B.Iron, air and water
C.Air, water and iron
D.Iron, water and air

83. One thousand microns is equal to

A.10^-3m
B.10^-6m
C.10^-9m
D.10^-12m

84. Superconductors are substances which

A.conduct electricity at low temperature
B.offer high resistance to the flow of current
C.offer no resistance to the flow of electricity
D.conduct electricity at high temperatures

Answer: Option C- offer no resistance to the flow of electricity

85. Choke is used to_______.
a) Reduce the current in AC circuit
b) Reduce the current in DC circuit
c) Convert AC to DC
d) Convert DC to AC

Answer is: a)Reduce the current in AC circuit

86.In a standing wave the distance between a node and adjacent antinode is______.
a) 3λ / 2
b) λ / 2
c) λ / 4
d) 3λ / 4

Answer is: c) λ / 4

87. Light travels at the fastest speed in

A.glass
B.water
C.hydrogen
D.vacuum

88. Railway tracks are banked on curves

A.necessary centrifugal force may be obtained from the horizontal component weight of the train
B.to avoid frictional force between the tracks and wheels
C.necessary centripetal force may be obtained from the horizontal component of the weight of the train
D.the train may not fly off in the opposite direction

Answer: Option C- necessary centripetal force may be obtained from the horizontal component of the weight of the train

89. The weight of a body is______.
a) The same everywhere on the surface of the earth
b) Maximum at the poles
c) Maximum at the equator
d) More on the hills than in the plains

Answer is: b)Maximum at the poles

90. At what temperature a body will not radiate any heat energy?
a) 0 oC
b) 273 oC
c) 100 oC
d) -273 oC