Question

what is the topic of cancer or topic of Capricorn

Answer 1

Tropic of cancer is the imaginary line or the 23 1/2°N latitude where the sun is directly overhead on 21st of June.
The tropic of Capricorn is the 23 1/2°S latitude. It is the southernmost latitude where the sun can be directly overhead. The area bounded between these two tropics is called as torrid zone.