The average kinetic energy of gas molecules is directly proportional to absolute temperature only. This implies that all molecular motion ceases if the temperature is reduced to absolute zero.

Correct Option: C

The average kinetic energy of gas molecules is directly proportional to absolute temperature only. This implies that all molecular motion ceases if the temperature is reduced to absolute zero.

We feel comfortable sitting under a fan when we are perspiring because a fan increases the rate of evaporation of sweat (or moisture) from our body and makes us feel cool and comfortable.

Correct Option: C

We feel comfortable sitting under a fan when we are perspiring because a fan increases the rate of evaporation of sweat (or moisture) from our body and makes us feel cool and comfortable.

A vehicle moving at a fast speed on a straight rail/ road has a large inertia, i.e. tendency to keep moving in the same direction at the same speed. When it takes a circular turn on a curved rail/road, it experiences an additional force, termed as centripetal force, acting towards the centre of the circle. While rounding the curve as the vehicle has tendency to leave curved path and regain straight line path, force of friction between wheels and ground provides necessary centripetal force. In order that the vehicle can go round the curved track at a reasonable speed without skidding, the sufficient centripetal force is managed for it by banking the rail/road.

Correct Option: C

A vehicle moving at a fast speed on a straight rail/ road has a large inertia, i.e. tendency to keep moving in the same direction at the same speed. When it takes a circular turn on a curved rail/road, it experiences an additional force, termed as centripetal force, acting towards the centre of the circle. While rounding the curve as the vehicle has tendency to leave curved path and regain straight line path, force of friction between wheels and ground provides necessary centripetal force. In order that the vehicle can go round the curved track at a reasonable speed without skidding, the sufficient centripetal force is managed for it by banking the rail/road.

Like gamma rays and neutrons, X-rays are electrically neutral. They have neither a positive nor a negative charge. They cannot be accelerated or made to change direction by a magnet or electrical field. In contrast, charged subatomic particles comprise light charged particles (electrons and positrons) and heavy charged particles (protons, alpha particles and heavier ions).

Correct Option: C

Like gamma rays and neutrons, X-rays are electrically neutral. They have neither a positive nor a negative charge. They cannot be accelerated or made to change direction by a magnet or electrical field. In contrast, charged subatomic particles comprise light charged particles (electrons and positrons) and heavy charged particles (protons, alpha particles and heavier ions).

The speed of sound in a medium is inversely proportional to the square root of its density. Higher is the humidity in the air, greater will be the velocity of sound. Therefore, the speed of sound in moist air is more than that in dry air. This is why the sirens of mills, whistle of trains and others are heard up to longer distances on a rainy day than on a dry day.

Correct Option: B

The speed of sound in a medium is inversely proportional to the square root of its density. Higher is the humidity in the air, greater will be the velocity of sound. Therefore, the speed of sound in moist air is more than that in dry air. This is why the sirens of mills, whistle of trains and others are heard up to longer distances on a rainy day than on a dry day.