Question

which ems wave has the longest wavelength (building - sized) and is used for communication? radio waves microwaves infrared visible

Explanation:

Among the given options, radio waves have the longest wavelength (can be building - sized) and are widely used for communication purposes. Microwaves have shorter wavelengths than radio waves. Infrared has even shorter wavelengths and is mainly used in applications like remote controls, thermal imaging etc. Visible light has relatively short wavelengths compared to radio waves and is used for vision etc.

Answer:

Radio Waves