If ${\lambda _v}$,${\lambda _x}$,and ${\lambda _m}$ represent the wavelengths of visible light,$X$-rays,and microwaves respectively,then:

If wavelengths of visible rays, microwaves, and $X$-rays are $\lambda_v$, $\lambda_m$, and $\lambda_x$ respectively, then which of the following relations is correct?

What are called heat waves?

Electromagnetic waves with wavelength:
$(i)$ ${\lambda _1}$ is used in satellite communication.
$(ii)$ ${\lambda _2}$ is used to kill germs in water purifiers.
$(iii)$ ${\lambda _3}$ is used to detect leakage of oil in underground pipelines.
$(iv)$ ${\lambda _4}$ is used to improve visibility in runways during fog and mist conditions.
$(a)$ Identify and name the part of the electromagnetic spectrum to which these radiations belong.
$(b)$ Arrange these wavelengths in ascending order of their magnitude.
$(c)$ Write one more application of each.

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R.$
Assertion $A:$ $EM$ waves used for optical communication have longer wavelengths than that of microwaves employed in $RADAR$ technology.
Reason $R:$ Infrared $EM$ waves are more energetic than microwaves (used in $RADAR$).
In the light of the given statements,choose the correct answer from the options given below:

If $\lambda_r$,$\lambda_v$,and $\lambda_x$ are the wavelengths of red light,violet light,and $X$-rays respectively,then which of the following relations is correct?