On a cold day when the room temperature is 15°C, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15°C, because : A. Metals have higher thermal capacity than plastics B. Plastics have a lower density than metals C. Metals are good conductors of heat D. Plastics have a higher thermal conductivity than metals

The correct answer is: C. Metals are good conductors of heat.

Metals are good conductors of heat because they have free electrons that can move easily. These free electrons can carry heat away from the metal, making it feel colder to the touch. Plastics, on the other hand, do not have free electrons, so they are not as good at conducting heat. This is

why the plastic body of the pen does not feel as cold as the metallic cap.

Here is a more detailed explanation of each option:

• A. Metals have higher thermal capacity than plastics. This is not true. Metals and plastics have similar thermal capacities. Thermal capacity is the amount of heat required to raise the temperature of a substance by one degree Celsius.
• B. Plastics have a lower density than metals. This is also not true. Metals and plastics have similar densities. Density is the mass of a substance per unit volume.
• C. Metals are good conductors of heat. This is true. Metals are good conductors of heat because they have free electrons that can move easily. These free electrons can carry heat away from the metal, making it feel colder to the touch.
• D. Plastics have a higher thermal conductivity than metals. This is not true. Metals have a higher thermal conductivity than plastics. Thermal conductivity is the ability of a substance to conduct heat.