* 7 millionths of a meter (7 x 10^-6 meters) is equivalent to 7 micrometers (µm). This falls within the infrared (IR) radiation range. Infrared radiation is associated with heat and is used in things like remote controls, thermal imaging, and night vision.
* 4 meters falls within the radio wave range. Radio waves are used for broadcasting, communication, and radar.
Let me know if you'd like to know more about specific types of infrared radiation or radio waves!
