Question

While Felicia is stirring her hot coffee with a metal spoon, she gets called away. She sets the coffee on the desk and then forgets to come back for it before going home for the weekend. How long will conduction between the spoon and the hot coffee occur?

Conduction will occur until the spoon is hotter than the coffee.
Conduction will occur until the spoon is at room temperature and the coffee gets cold.
Conduction will occur until the spoon is removed from the coffee after the weekend.
Conduction will occur until the spoon and coffee are the same temperature.

Answer 1

Conduction occurs as long as there is a temperature difference between the spoon and the coffee. It will continue until the spoon and coffee reach the same temperature (thermal equilibrium). After that point there is no net heat flow between them.