Question

you pour hot coffee into a metal mug and leave it on your counter. which statement best describes how thermal energy will flow between the coffee, the mug, and the surrounding air over the next hour? a. thermal energy will flow from the surrounding air into the mug and then into the coffee until all parts are equally warm. b. thermal energy will flow from the hot coffee to the mug and then to the surrounding air until all reach the same. c. the coffee will stay hot because the metal mug prevents heat transfer to the surrounding air. d. thermal energy will move back and forth evenly between the coffee and the air, keeping both at a constant temperature.

Explanation:

Thermal energy (heat) always flows from a region of higher temperature to a region of lower temperature. The hot coffee has a higher temperature than the mug, and the mug (which gets heated by the coffee) has a higher temperature than the surrounding air. Heat transfer will continue until thermal equilibrium (all at the same temperature) is reached.

• Option A: Thermal energy flows from hot to cold. Since coffee is hot (higher - temperature initially), heat won't flow from air (lower - temperature initially) to coffee.
• Option B: Coffee (hot) transfers heat to mug (initially cooler), then mug (now warmer than air) transfers heat to air. This continues until thermal equilibrium.
• Option C: Metal is a good conductor of heat. It won't prevent heat transfer.
• Option D: Thermal energy doesn't move back and forth evenly to keep temperatures constant. Heat transfer is unidirectional from hot to cold until equilibrium.

Answer:

B. Thermal energy will flow from the hot coffee to the mug and then to the surrounding air until all reach the same temperature.