Question

why black holes do not emit light??​

Answer 1

Because the escape velocity for black hole is more than the speed of light so it doesn't emits light.

Answer 2

Answer:

a black hole is a region where spacetime is so curved that every possible path which light could take eventually curves and leads back inside the black hole. as a result, once a ray of light enters a black hole it can never exit.

that's why a black hole is truly black and never emits light.