41.

Light travels at the fastest speed in
A. glass B. water
C. hydrogen D. vacuum
Answer and Explanation
Answer:D
Explanation: No answer description available for this question.
42.

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 and Explanation
Answer:C
Explanation: No answer description available for this question.
43.

On a cold day when a room temperature is 15oC, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15oC, because
A. metals have higher thermal capacity than plastics B. plastics have a lower density than metals
C. metals are good conductor of heat D. plastics have a higher thermal conductivity than metals
Answer and Explanation
Answer:C
Explanation: No answer description available for this question.
44.

Sound produced at a point is heard by a person after 5 second, while the same sound is heard by another person after 6 seconds. If the speed of sound is 300 m/s, what could be the maximum and minimum distances between the two persons?
A. 1.8 km, 0.15 km B. 2.2 km, 0.20 km
C. 2.8 km, 0.25 km D. 3.3 km, 0.30 km
Answer and Explanation
Answer:D
Explanation: No answer description available for this question.
45.

Intensity of sound at a point is ____ its distance from the source.
A. directly proportional to B. inversely proportional to
C. directly proportional to square of D. inversely proportional to square of
Answer and Explanation
Answer:D
Explanation: No answer description available for this question.