100 g of a copper body at 60°C is cooled to 40°C. How much heat does it release? [Ans. 780 cal]
To calculate the heat released by a 100 g copper body when it is cooled from 60°C to 40°C, we can use the formula:
Heat = Mass × Specific heat × Temperature change
Mass of copper body (m) = 100 g
Specific heat of copper (s) = 0.39 cal/g/°C
Temperature change (ΔT) = (40°C – 60°C) = -20°C (negative since it is a decrease in temperature)
Heat = 100 × 0.39 × -20
Heat = – 780 cal
The negative sign indicates that heat is being released by the copper body.
Therefore, the copper body releases approximately 780 cal of heat when it is cooled from 60°C to 40°C.