What type of wave has the longest wavelength and the lowest frequency?

Infrared radiation has wavelengths between 700 nm and 1 millimeter (mm). In infrared the detected radiation is turned into an image on a screen, hotter objects showing up brighter. Radio waves have the longest wavelengths in the electromagnetic spectrum.

The frequency of a wave is inversely proportional to its wavelength. That means that waves with a high frequency have a short wavelength, while waves with a low frequency have a longer wavelength. Light waves have very, very short wavelengths.

Radio Waves — The waves in the electromagnetic spectrum that have the longest wavelengths and lowest frequency are called radio waves. Radio waves are used to transmit information from the antenna of a broadcasting station to the antenna of your radio or TV.