Physics 2009 JAMB Past Questions - Question 25: A man standing 2m from a charcoal fire is warmed mainly by

Correct Answer

B

Explanation

A man standing 2 meters from a charcoal fire is primarily warmed by three different mechanisms: radiation, conduction, and convection.

1. **Radiation:** The man is primarily warmed by the radiant heat emitted by the charcoal fire. Infrared radiation is released from the hot charcoal and travels through the air to reach the man. This is the most significant source of heat transfer, especially when standing at a distance.

2. **Conduction:** If the man is in close proximity to objects that are heated by the fire, he may also be warmed through conduction. For example, if he's touching a metal surface or sitting on a hot object, heat can be transferred from those surfaces to his body through direct contact.

3. **Convection:** Convection involves the transfer of heat through the movement of air or fluids. Near a fire, hot air rises, and cooler air is drawn in to replace it. This circulation of air can also contribute to the man feeling warmer, as the warmer air displaces the cooler air around him.

Radiation is usually the most significant factor at a distance of 2 meters from the fire, but convection and conduction can play a role if the man is in closer proximity to the fire or hot objects.