$\textit{a.}$, X-rays are used in baggage screening.

$\textit{b.}$, Ultraviolet light - Vitamin D

$\textit{c.}$, Radio waves are used in radar communications.

$\textit{d.}$, Infrared light - DVD player, remote control

$\textit{e.}$, Microwaves are used in telecommunications.

$\textit{f.}$, Gamma rays are used in cancer treatment.

$\textit{g.}$, Visible light is used in theatre/concert effects

a. X-rays are used in baggage screening.