Practice MCQ Questions and answers on Physics-GK

In a railway track, two rails are joined end to end with a gap in between them because accidents due to expansion in summer can be avoided.

Air coolers are more suitable for hot and dry climate.

A fan produces a feeling of comfort because our perspiration or sweating evaporates rapidly. Our body tries to cool ourselves by releasing sweat through pores of our skin. And when we sit under the fan, the sweat of our body evaporates due to directed air upon us making our body cool.

If the poured liquid is relatively hotter or colder in comparison to the tumbler, it will break. When hot water is poured into a tumbler there is an uneven increase in the thermal expansion of the walls of the vessel.

A gap is left between two rails of a railway track to accommodate linear expansion of the metal.

Silver, Copper, Aluminium, Steel is arranged in order of decreasing conductivity.

Every hot object emits infrared rays.

Silver is indeed the best conductor of heat among the metals listed in the options. It has the highest thermal conductivity of all metals and is known for its exceptional ability to conduct heat efficiently.

So, the correct answer is Option A: Silver when considering the best conductor of heat among the provided options. Thank you for pointing out the clarification.

When hot liquid is poured into a thick glass tumbler, it cracks because glass is a bad conductor of heat so only inner surface expands.

Clay is a poor conductor of heat as compared to wood and bricks. Therefore, clay neither allows the external heat to enter the house in summer nor it allows the internal heat to escape out in winters. Hence, mud houses remain colder in summer and warmer in winter. mud or clay is poor conductor of electricity.