How it works
These 27 electromagnetic spectrum questions come in two sets: the seven bands, their order and what each is used for, then how wavelength, frequency and energy compare from radio waves to gamma rays.
Read the full guide
Two sets
The seven bands and their uses asks which band is longest, which lies next to visible light, and which one a remote control, a GPS receiver or a picture of bones uses. Wavelength, frequency and energy compares the bands: which has the higher frequency, which carries more energy, and why all of them travel at one speed.
Numbers in the questions
Visible light runs from about 380 nanometers (violet) to about 700 (red). The one calculation uses 300,000,000 meters per second, the rounded speed of light.
- A longer wavelength means a lower frequency and less energy; a shorter one means more of both.
- Infrared is just beyond red light, ultraviolet just beyond violet.
Questions and answers
What are the 7 types of electromagnetic waves in order?
From the longest wavelength to the shortest: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays. Read the other way, the list runs from the highest frequency to the lowest.
Which electromagnetic wave has the highest frequency?
Gamma rays. They have the shortest wavelengths and the most energy of any band. Radio waves are at the other end, with the lowest frequency and the longest wavelengths.
Do all electromagnetic waves travel at the same speed?
In empty space, yes. Radio waves, light and gamma rays all travel at the speed of light, about 300,000 kilometers each second. They differ in wavelength and frequency, not in speed.
What is the electromagnetic spectrum used for?
Each band has its uses. Radio waves carry broadcasts, microwaves carry satellite signals and heat food, infrared works remote controls, visible light is what we see by, and X-rays make pictures of bones.