Question

As you heat up a substance it will glow "red hot" before it glows "white hot". This is because

		red light moves slower than other colored light.
		red light moves faster than other colored light.
		red light has more energy than other colored light.
		red light has less energy than other colored light.

Answer 1

Fourth option, 'red light has less energy than other colored light' is the correct answer.

Explanation -

I think you remember the rainbow, ROYGBIV. Well, red light has the longest wavelength, which means it has the lowest energy photon.

The radiation that hot surfaces result from electrons jumping from one orbital to other. The lower energy transitions occur at lower temperatures than the higher energy transitions. They produce infra-red light first, then red then orange then white etc.