Identify the correct arrangement of the following electromagnetic waves in the ascending order of th

Question

Identify the correct arrangement of the following electromagnetic waves in the ascending order of their energy:
(I) Visible light
(II) Radio waves
(III) X-rays
(IV) Microwaves
Select the most appropriate option:

Professor PC Thomas Classes · Answer

The energy of an electromagnetic wave is directly proportional to its frequency ( $\boldsymbol{\boldsymbol { E } ^ { \prime }}=\boldsymbol{h} \boldsymbol{f}$ ) and inversely proportional to its wavelength ( $\boldsymbol{\boldsymbol { E } ^ { \prime }}=\boldsymbol{h} \boldsymbol{c} / \boldsymbol{\lambda}$ ), where $\boldsymbol{h}$ is Planck's constant and $\boldsymbol{c}$ is the speed of light. Therefore, waves with higher frequency (and shorter wavelength) have higher energy.
Let's list the given electromagnetic waves and their general order in the electromagnetic spectrum from lowest energy to highest energy:(II) Radio waves < (IV) Microwaves < (I) Visible light < (III) X-rays
So, $E_{I I}<E_{I V}<E_I<E_{I I I}$.