Which term refers to the electromagnetic radiation visible to the human eye?

• A. The electromagnetic radiation visible to the human eye
• B. A measure of brightness of a light source
• C. A form of chemical energy stored in foods
• D. A type of sound energy in water

Answer: (A)

Visible light is the portion of the electromagnetic spectrum detectable by the human eye. It spans roughly 380 to 740 nanometers in wavelength and is perceived as colors from violet to red. This term specifically refers to electromagnetic radiation that humans can see, which is why it is the correct choice.

The other options describe concepts that are not electromagnetic radiation: a measure of brightness relates to how bright a light appears rather than what type of radiation it is; chemical energy stored in foods is energy content in chemistry; and sound energy in water is mechanical energy transmitted as pressure waves.