How are $X$-rays produced in the laboratory?

The emission of continuous $X$-rays is due to:

An $X$-ray tube produces a continuous spectrum of radiation with its shortest wavelength of $45 \times 10^{-2} \text{ Å}$. The maximum energy of a photon in the radiation in $eV$ is (in $27,500$). $(h = 6.62 \times 10^{-34} \text{ J-s}, c = 3 \times 10^8 \text{ m/s})$.

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:

$X$-rays incident on a material:

If the frequency of $K_\alpha$ $X$-rays emitted from the element with atomic number $31$ is $v$,then the frequency of $K_\alpha$ $X$-rays emitted from the element with atomic number $51$ would be: