Which of the following waves are associated with communication?

The frequencies of $X$-rays,$\gamma$-rays,and ultraviolet rays are $a, b$,and $c$ respectively. Which of the following relations is correct?

To which region of the electromagnetic spectrum does the frequency $1\, GHz$ correspond?

The device used to detect infrared radiations is

Consider the following statements regarding the electromagnetic spectrum:
$(A)$ The wavelength of microwaves is greater than that of $UV$ rays.
$(B)$ The wavelength of $IR$ rays is less than that of $UV$ rays.
$(C)$ The wavelength of microwaves is lesser than that of $IR$ rays.
$(D)$ Gamma rays have the shortest wavelength in the electromagnetic spectrum.
Which of the above statements are true?

Which rays are not a portion of the electromagnetic spectrum?