Which of the following rays has the maximum frequency?

The electromagnetic waves of frequency $2 \ MHz$ to $30 \ MHz$ are used in:

Match the following types of waves with their wavelength ranges:

$i$. Microwave	$(a)$. $700 \ nm$ to $400 \ nm$
$ii$. Visible light	$(b)$. $1 \ nm$ to $10^{-3} \ nm$
$iii$. Ultraviolet	$(c)$. $0.1 \ m$ to $1 \ mm$
$iv$. $X$-rays	$(d)$. $400 \ nm$ to $1 \ nm$

Which of the following statements is wrong?

Which of the following groups of electromagnetic waves is in increasing order of frequency?

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.