Question

What are white dwarf ? And the difference between white hole and black hole.

Answer 1

White dwarf are "the stars which used up all its fuels ". As they used all its fuel so can not continue nuclear fision so can not produce more energy and temperature.
a white hole is considered the opposite of a black hole. It is a hypothetical region of space which cannot be entered from the outside, so light and mass can escape from it.
black holes are very massive. balck hole is the last stage of any star. it absobs everything. Light and mass can not escape it.
black holes form when a very massive star collapses in upon itself.