Question

What occurs when the direct sun rays hit a tropical line?

Answer 1

When the direct rays of the Sun hit the equator, it is either the Vernal (Spring) Equinox or the Autumnal Equinox, when there are 12 hours of sunlight and 12 hours of darkness in one 24 hour day. 

When the direct rays of the Sun hit the Tropic of Cancer it is the Summer Solstice in the Northern Hemisphere. The day of the year with the most sunlight hours in the Northern Hemisphere, and the least sunlight hours in the Southern Hemisphere. 

When the direct rays of the Sun hit the Tropic of Capricorn it is the Winter Solstice in the Northern Hemisphere. The day of the year with the least sunlight hours in the Northern Hemisphere, and the most sunlight hours in the Southern Hemisphere.