How does a Neutron Star emit light energy if it is already a remnant of a dead star?

yes how i remember that is the moon reflects and the stars are opposite..Wonderful. The way I remember it is to remind myself that I can see them.

Stars produce energy from nuclear fusion. In the hot, dense interior of the star, hydrogen nuclei (that is to say, protons) smash into other hydrogen nuclei with enough force that they fuse together...

Stars emit light because they are hot - with typical surface temperatures of a few thousand kelvin. And they are hot because they convert energy in their cores, in a process called nuclear fusion.

Black dwarfs of black holes.

Yes, they do emit a little amount of light.