Question

which of the following is an example of convection?
multiple choice
exposure of the body to cold air
infrared radiation
sweating
losing water to the air
warming a chair by sitting in it

Explanation:

• Exposure of the body to cold air: Convection is the transfer of heat through the movement of fluids (liquids or gases). When the body is exposed to cold air, the cold air (a fluid) moves and takes away heat from the body. This is an example of convection.
• Infrared radiation: This is an example of heat transfer by radiation. Radiation is the transfer of heat in the form of electromagnetic waves (like infrared rays) and does not require a medium (fluid or solid).
• Sweating: Sweating is a form of evaporative cooling. When sweat (a liquid) evaporates from the skin, it takes away heat from the body. This is an example of heat transfer by evaporation (a type of phase - change heat transfer).
• Losing water to the air: Similar to sweating, this is also related to evaporation. Water (from the body or other sources) evaporates into the air, taking away heat in the process.
• Warming a chair by sitting in it: This is an example of heat transfer by conduction. Conduction is the transfer of heat through direct contact between solids. When you sit on the chair, heat is transferred from your body (a solid) to the chair (another solid) through direct contact.

Answer:

Exposure of the body to cold air