Final answer:
When the block of metal cools by 10°C, it releases some of the energy it previously absorbed. The specific heat capacity determines how much energy is released during the cooling process.
Step-by-step explanation:
When the heater supplies 80 J of energy to a block of metal and the temperature of the block rises by 20°C, the block absorbs that energy, increasing its internal energy and thereby raising its temperature. If its temperature then falls by 10°C, the block releases some of that energy into the environment, usually in the form of heat, as it cools down. The amount of energy released would depend on the specific heat capacity of the metal and its mass.
Check Your Understanding: If 25 kJ is necessary to raise the temperature of a block from 25°C to 30°C, then the same amount of heat, 25 kJ, would be necessary to heat the block from 45°C to 50°C because the temperature change is the same and we are assuming no change in the block's heat capacity or other conditions.