Question

Account for the unequal length of day and night.

Answer 1

The length of day and night varies throughout the year. Sometimes the days are longer and nights are shorter and vice versa. It is due to two reasons :

(a) The inclination of the axis.
(b) The revolution of the Earth.

Due to the inclined axis, one hemisphere leans towards the Sun for the six months; the other Hemisphere leans towards the Sun for the next six months. In summer, on 21st June, days are longer in the Northern Hemisphere and the nights are shorter. In winter, the conditions are reversed, the days are shorter and nights are longer in the Northern Hemisphere. If the axes were vertical, there would have been equal days and nights everywhere.