Which of the following is an electromagnetic wave?

The frequency of a wave is $6 \times 10^{15} \text{ Hz}$. This wave is:

Choose the correct option relating the wavelengths of different parts of the electromagnetic wave spectrum.

$(i)$ The wavelength of microwaves is greater than that of $UV$-rays.
$(ii)$ The wavelength of $IR$ rays is less than that of $UV$-rays.
$(iii)$ The wavelength of microwaves is lesser than that of $IR$ rays.
$(iv)$ Gamma rays have the shortest wavelength in the electromagnetic spectrum.
Of the above statements:

The waves having maximum wavelength among the following electromagnetic waves is

The power of a source is $4 \, kW$. If it produces $10^{20}$ photons in $1 \, s$,then the radiation emitted from this source belongs to which part of the electromagnetic spectrum?