In this scenario, the fact that the cup with the metal spoon ends up with a lower temperature than the cup without the spoon indicates that energy is being transferred from the coffee to the spoon.
The most suitable explanation for this situation is option A: Energy is removed from the coffee mostly by conduction through the spoon.
1. Conduction is the transfer of heat through a material by direct contact of particles. In this case, the metal spoon, being a good conductor of heat, absorbs heat energy from the coffee when they are in contact. The heat from the coffee moves through the spoon to the surroundings, causing the coffee to cool down.
2. Convection involves the transfer of heat through the movement of fluids (liquids or gases). Since the coffee is not actively circulating like a fluid, convection is less likely to be the primary mechanism for heat transfer in this scenario.
3. Radiation is the transfer of heat through electromagnetic waves. While radiation can contribute to heat transfer, especially at high temperatures, in this case, the direct contact of the spoon with the coffee is the dominant mechanism of heat transfer leading to the cooling of the coffee.
Therefore, the most reasonable explanation for the cooling of the coffee in the cup with the spoon is that energy is primarily being removed from the coffee through conduction via the metal spoon.
