Physics - Study Mode

[#216] Oil raise up the wick in a lamp. The principle involves
Correct Answer

(C) capillary action phenomenon

Explanation

Solution: The raise of oil up the wick in a lamp is an example of capillary action where adhesive forces are greater than cohesive forces.

[#217] Superconductors are substances which
Correct Answer

(C) offer no resistance to the flow of electricity

Explanation

Solution: By definition, superconductors are substances which display zero electrical resistance when a current is supplied, and are able to propagate such a current in a circuit indefinitely.

[#218] Light travels at the fastest speed in:
Correct Answer

(D) vacuum

Explanation

Solution: Light travels at the fastest speed in Vacuum.

[#219] Railway tracks are banked on curves
Correct Answer

(C) necessary centripetal force may be obtained from the horizontal component of the weight of the train

Explanation

Solution: When a fast moving train takes a curved path, it tends to move away tangentially off the track. In order to prevent this, the curved tracks are banked on the outside to produce the necessary centripetal force required to keep the train moving in a curved path.

[#220] On a cold day when a room temperature is 15 o C, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15 o C, because
Correct Answer

(C) metals are good conductor of heat

Explanation

Solution: Metals are good conductor of heat.