General Knowledge - World Geography - Discussion

Because the earth is tilted at 23.5° and as it orbits the sun different parts of the earth are nearer to the sun, making it seem higher in the sky or lower in the sky. The closer you are to the the equator, the less of a difference there is in the length of the day throughout the year.

By the December 21st, the northern hemisphere is tilted as far away as it can be, making the days shortest in the northern hemisphere and longest in the southern hemisphere. By June 21st, the northern hemisphere is tilted at the maximum towards the sun and the longest days are in the northern hemisphere.

So answer should be C.

It is because of inclination of earth axis of rotation combined with earth revolution around the sun causes variation in the duration of Day & Night. The answer B & C would have been correct had the inclination angle given in option C is either 23.4 deg or 66.6 deg.

Rotation of earth causes days and nights.

But revolution of earth around sun makes changes in the duration of days and niht.

Therefore both rotation and revolution of earth affects the duration of days and nights.