Q. On June 21, over which geographical line is the Sun vertically overhead?
Answer: Tropic of Cancer
Notes: On June 21st, the Sun stands exactly over the Tropic of Cancer. This date marks the Summer Solstice in the Northern hemisphere as the Sun reaches its highest point in the sky. Conversely, this is the Winter Solstice on the Tropic of Capricorn in the Southern Hemisphere, typically observed on December 21st. The Tropics of Cancer and Capricorn are the two imaginary lines located at 23.5 degrees north and south of the equator respectively. They indicate the furthest points north and south where the Sun can be seen directly overhead at noon.