When an $X$-ray tube operates at $60 \ kV$,the observed tube current is $50 \ mA$. Assuming that the total energy of the electrons is converted into heat,the rate of heat production at the anode in $cal/s$ is:

The Compton effect is associated with

For an $X$-ray tube operating at $40 \, kV$, which of the following wavelengths is $NOT$ possible?

The largest distance between the interatomic planes of a crystal is $10^{-7} \text{ cm}$. The upper limit for the wavelength of $X$-rays which can be usefully studied with this crystal is ............ $\mathring{A}$.

When $0.50\; \mathring{A}$ $X$-rays strike a material,the photoelectrons from the $K$-shell are observed to move in a circle of radius $23\; mm$ in a magnetic field of $2 \times 10^{-2}\; T$ acting perpendicularly to the direction of emission of photoelectrons. The binding energy of $K$-shell electrons is $..........\; keV$.

Penetrating power of $X$-rays increases with an increase in