Question

Electromagnetic waves are classified into forms such as radio waves, microwaves, and infrared waves, based on the amount of energy they carry. Which property of an electromagnetic wave determines the level or amount of energy it carries?
A) speed
B) intensity
C) phase
D) wavelength

Answer 1

Answer: D) wavelength

Explanation:

The energy $E$ of an electromagnetc wave is given by the following formula:  

$E=h.f$ (1)

Where:  

$h$ is the Planck constant  

$f$ is the frequency  

Now, the frequency has an inverse relation with the wavelength $\lambda$:  

$f=\frac{c}{\lambda}$ (2)  

Where $c$ is the speed of light in vacuum

Substituting (2) in (1) we have:

$E=\frac{hc}{\lambda}$ (3)

This means the amount of energy an electromagnetic wave carries depends on its wavelength (or its frequency), because the speed of light and $h$ are constant.

Answer 2

Answer:

The property is D) wavelength.

Explanation:

Wavelength can be found by the distance between successive points on a wave. It can be consecutive corresponding crests, troughs or zero crossings. We can get the most accurate form of wavelength on sinusoidal waves, which are smooth and repetitive.

Two waves which are travelling with the same rate of speed can have different wavelength with varied frequencies. A light’s wavelength varies with varying color.

For example: the wavelength of red is longer than violet.