The electromagnetic ($E$.$M$.) wave with the shortest wavelength among the following is:

Light of wavelength $1 \,nm$ belongs to the following class of waves:

Why does human skin darken when exposed to sunlight for a long period of time?

In household appliances,which waves are used to operate remote control switches?

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.

Match the List-$I$ (Phenomenon associated with electromagnetic radiation) with List-$II$ (Part of electromagnetic spectrum) and select the correct code from the choices given below:

List-$I$	List-$II$
$I$. Doublet of sodium	$A$. Visible radiation
$II$. Wavelength corresponding to temperature associated with the isotropic radiation filling all space	$B$. Microwave
$III$. Wavelength emitted by atomic hydrogen in interstellar space	$C$. Short radio wave
$IV$. Wavelength of radiation arising from two close energy levels in hydrogen	$D$. $X$-rays