Two identical metal bars are heated up until they are both glowing. One of them is "red hot" and the other is "blue hot." Which one is hotter, the one that glows red or the one that glows blue?
A) the red one
B) the blue one
C) We cannot tell without knowing more about the two bars.

Question

Quizplus · Accepted Answer

The color of a glowing object due to heat is an indicator of its temperature. Objects that glow blue are hotter than those glowing red. This is because blue light has a shorter wavelength and higher energy than red light, indicating a higher temperature for the blue glowing object.

Two Identical Metal Bars Are Heated Up Until They Are