Chapter 21, Problem 31A

To determine

Whether the same principle of thermal equilibrium hold true when rock is dropped in large lake.

Explanation of Solution

Introduction:When a hot rock is dropped into a pail of water then the temperature of the rock drops and water warms up because both objects try to maintain thermal equilibrium. Thus, hot rock transfers its heat to the cool water until both achieve the same temperature.

When a hot rock is dropped in a lake of water, then due to thermal conductivity and heat exchange, the hot rock will transfer its heat to the cool water and cool water starts to warm. But, here the warm water will again transfer its heat to the surrounding cool water in the same lake and which intends to bring it to the same temperature it was before, to maintain the thermal equilibrium.

Conclusion: Thus, yes, heat exchange will occur but effects will be negligible.