Q. What is the electromagnetic spectrum?
Ans.
Light is a very small slice of the electromagnetic spectrum, just the wavelengths that our eyes can see, which range from about 380nm to 760nm.
Radio waves are the longest electromagnetic waves (from 0.1 m and upward). As you might have guessed radio waves are used to carry
radio signals. Aircraft and ships use the longer wavelength end of the radio band; AM radio is slightly shorter and; TV and FM radio are on
the short side of the radio wavelengths.
Slightly shorter than radio waves are microwaves( between 0.1 m and m). Other than their obvious use in microwave ovens, microwaves are also used in radar guns like the ones that the police use to detect speeding cars.
Right next to the visible spectrum, but still undetectable to the human eye are the infrared wavelength (m to 800 nm). Night vision goggles pick up infrared light from our bodies. Body heat emits infrared radiation.