Which of the following is an example of heat transfer by radiation?
A. Wind currents.
B. A pot of water on a boiling stove.
C. A bare foot on a hot sidewalk.
D. A microwave oven heating food.
Is it B?
Microwaves produce radiation. So it is D?
radiation? What is a microwave magnetron producing?
I wonder what a boiling stove is?
Yes, option B is an example of heat transfer by radiation. To understand why it is the correct answer, let's first understand the concept of heat transfer by radiation.
Heat transfer by radiation occurs when energy is transferred in the form of electromagnetic waves. Unlike conduction or convection, radiation can occur without the need for a material medium to propagate the heat. In other words, radiation can transfer heat through a vacuum (empty space) as well.
Now, let's apply this knowledge to the options given.
A. Wind currents: This is an example of heat transfer by convection, not radiation. Convection involves the transfer of heat through the movement of a fluid (liquid or gas).
B. A pot of water on a boiling stove: This is an example of heat transfer by conduction, not radiation. Conduction occurs when heat is transferred through direct contact between two objects at different temperatures.
C. A bare foot on a hot sidewalk: This is an example of heat transfer by conduction, not radiation. The hot sidewalk would conduct the heat to your foot upon contact.
D. A microwave oven heating food: This is an example of heat transfer by radiation, specifically by microwaves. Microwaves are a form of electromagnetic waves that excite the water molecules in the food, causing them to vibrate and generate heat.
Therefore, option D, a microwave oven heating food, is the correct example of heat transfer by radiation. The electromagnetic waves (microwaves) emitted by the microwave oven penetrate the food and cause it to heat up without the need for direct contact or a medium to transfer the heat.