A red hot steel bar is an example of:

When a steel bar is heated to a high temperature, it becomes "red hot" and starts to glow. At this stage it gives out two forms of energy together: heat energy (felt as warmth radiating from the bar) and light energy (seen as the red glow).

This phenomenon is called incandescence — the emission of visible light by a body purely because of its high temperature. As the bar gets even hotter, its glow shifts from red to orange, yellow and finally white, but throughout it is radiating both heat and light.

Therefore, a red hot steel bar is a familiar everyday example of a source of heat and light energy.