A) Radio wave
Explanation:
Electromagnetic waves are periodic oscillations of the electric and the magnetic fields in a plane perpendicular to the direction of motion the wave. (they are transverse in nature).
All electromagnetic waves travel in a vacuum at the same speed, the speed of light:
[tex]c=3.0\cdot 10^8 m/s[/tex]
Moreover, electromagnetic waves are classified into 7 different types, depending on their wavelength/frequency. From the shortest to the longest wavelength (highest to lowest frequency), they are:
Gamma rays [tex]<10^{-12} m[/tex]
X rays [tex]1nm-1pm[/tex]
Ultraviolet [tex]380 nm - 1 nm[/tex]
Visible light [tex]750 nm - 380 nm[/tex]
Infrared radiation [tex]25 \mu m - 2.5 \mu m[/tex]
Microwaves [tex]1 mm - 25 \mu m[/tex]
Radio waves [tex]> 1 mm[/tex]
As we can see from the table, radio waves are the electromagnetic waves with longest wavelength, as their wavelength is larger than 1 mm (can be either several metres or several kilometres). Therefore, the wave in the problem (14 m) is an electromagnetic wave.
Radio waves are generally used for long-distance telecommunications (satellite or TV communications).
