Practice MCQ Questions and answers on Physics-GK

A small gap is left at the joints of rails in a railway track to avoid the tracks being distorted due to seasonal temperature variation.

Water in pipes freeze in cold countries. Due to the anomalous expansion of water, it expands instead of contacting when there is a fall in temperature below 4°c. So, the water pipes burst due to the excess space consumed by the ice after freezing.

Water in pipes freeze in cold countries. Due to the anomalous expansion of water, it expands instead of contacting when there is a fall in temperature below 4°c. So, the water pipes burst due to the excess space consumed by the ice after freezing.

Railway tracks are banked at the curves so that the necessary centripetal force may be obtained from the horizontal component of the reaction on the train.

When a liquid is heated, its volume increases and mass of liquid being same density decreases.

A thermocouple consists of two dissimilar metals, joined together at one end. When the junction of the two metals is cooled or heated a voltage is produced that can be correlated back to the temperature. Most thermocouple alloys are commonly available as wire.

An especially notable irregular maximum density is that of water, which reaches a density peak at 3.98°C (39.16°F) approximately 4^oC.

When water freezes its density decreases. Water at ordinary temperatures contracts and increases in density as it is cooled, like most substances. But at about 4°C it reaches a maximum density and then decreases in density as it approaches the freezing point.

The three types of heat transfer
Heat is transfered via solid material (conduction), liquids and gases (convection), and electromagnetical waves (radiation). Heat is usually transfered in a combination of these three types and seldomly occurs on its own.

Conduction is heat transfer through stationary matter by physical contact.