Arrange the following electromagnetic waves in increasing order if their frequencies: Visible light, $\mathrm{\gamma }$-rays, X-rays, microwaves, radio waves, infrared radiations and ultraviolet radiations.

In which part of the electromagnetic spectrum do the following radiations lie:

(i) Having a wavelength of $20\mathrm{nm}$ 

To which regions of the electromagnetic spectrum do the following wavelength belongs :

(a) $250$nm

To which of the electromagnetic spectrum do the following wavelengths belong:

(b)1500nm