A cycle pump becomes hot near the nozzle after a few quick strokes even if they are smooth because

A bicycle pump becomes hot when air is pumped into the tube. Why?

Why does a dry cell become dead after a long time even if it has not been used ?

Why does a dry cell become dead after a long time, even if it has not been used?

Why does a dry cell becomes dead after a long time even if it has not been used?

Why does a dry cell become dead after a long time even if it has not been used?

Give reason why does a dry cell become dead after long time even if has not been used?

Why a dry cell becomes dead after a long time even if it is not used ?

Why a dry cell becomes dead after a long time even if it is not used ?

It is said that the sun becomes visible before the actual rise and remains visible even after the actual setting. This makes the day a bit longer. It happens due to :