What is called as the electromagnetic spectrum?

The wavelengths of Gamma rays,$X$-rays,and microwaves are respectively $\lambda_r, \lambda_x$,and $\lambda_m$. Then which of the following relations is correct?

The decreasing order of wavelength of infrared,microwave,ultraviolet,and gamma rays is:

If a source of electromagnetic radiation having power $15 \text{ kW}$ produces $10^{16}$ photons per second,the radiation belongs to which part of the spectrum? (Take Planck constant $h = 6 \times 10^{-34} \text{ Js}$)

Which of the following electromagnetic waves has the shortest wavelength?

$TV$ waves have a wavelength range of $1-10 \, m$. Their frequency range in $MHz$ is