An electromagnetic wave of wavelength 14m is best classified as _.

A. a radio wave
B. infrared radiation
C. ultraviolet radiation
D. a gamma ray

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:

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

X rays

Ultraviolet

Visible light

Infrared radiation

Microwaves

Radio waves

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).

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.