Question

If a cup of coffee is at 90°C and a person with a body temperature of 36°C touches it, how will heat flow between them?

from the hand to the cup
from the cup to the hand
from the cup to the surrounding air
from the hand to surrounding air

Answer 1

Heat will flow from the cup to the hand. This is because heat transfers from a region of higher temperature to a region of lower temperature. In this case, the coffee cup is at 90°C (hotter) and the person's hand is at 36°C (cooler).

Additionally, the heat can also flow from the cup to the surrounding air, as the cup is still at a higher temperature compared to the ambient air. However, when referring specifically to the interaction between the hand and the cup, the heat flow is from the cup to the hand.

As for the options you provided:
1. **from the hand to the cup** - Not correct, as the hand is cooler.
2. **from the cup to the hand** - Correct, heat flows from the cup to the hand.
3. **from the cup to the surrounding air** - Possible, but not the primary interaction in this context.
4. **from the hand to surrounding air** - Possible, but again not the primary interaction with the cup.

So, the primary heat transfer in this scenario is from the cup to the hand.