The electromagnetic ($E$.$M$.) wave with the shortest wavelength among the following is:

If a source of power $4 \ kW$ produces $10^{20}$ photons/second,the radiation belongs to a part of the spectrum called

The electromagnetic waves of frequency $2 \ MHz$ to $30 \ MHz$ are used in:

If microwaves,$X$ rays,infrared,gamma rays,ultraviolet,radio waves and visible parts of the electromagnetic spectrum are denoted by $M, X, I, G, U, R$ and $V$ respectively,then which of the following is the arrangement in ascending order of wavelength?

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$(a)$ Ultraviolet rays	$(i)$ Study crystal structure
$(b)$ Microwaves	$(ii)$ Greenhouse effect
$(c)$ Infrared waves	$(iii)$ Sterilizing surgical instruments
$(d)$ $X$-rays	$(iv)$ Radar system

Choose the correct answer from the options given below:

If $\lambda_v$,$\lambda_x$,and $\lambda_m$ are the wavelengths of visible light,$X$-rays,and microwaves respectively,then which of the following is correct?