Question

which is the indicator of heat /thermal energy​

Answer 1

Answer:

We can't see an object's thermal energy, but there is a common indicator: temperature. As an object's thermal energy increases, it's temperature increases, and as an object's thermal energy decreases, its temperature decreases.

Answer 2

$\huge\mathcal{Answer:}$

Change in temperature is an indicator of thermal energy. Thermal energy is transferred from the hand warmer to the hands of the person holding it. In another type of hand warmer you read about, a chemical change takes place.