Which of the following waves is used in a speed gun to measure the speed of a ball in a cricket match?

$A$ source of power $4 \ kW$ emits $10^{20}$ photons in $1 \ s$. In which region of the electromagnetic spectrum does the emitted radiation lie?

One requires $11 \ eV$ of energy to dissociate a carbon monoxide molecule into carbon and oxygen atoms. The minimum frequency of the appropriate electromagnetic radiation to achieve the dissociation lies in

What is the frequency range of $AM$ radio waves?

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?

Which of the following electromagnetic radiations has the smallest wavelength?