$X$-rays incident on a material:

If the energy of an electron in the $K$-shell is $40000 \,eV$ and an accelerating potential of $60000 \,eV$ is applied across a Coolidge tube,which of the following $X$-rays will be obtained?

The energy of the $L$ shell is $7200$ units and the energy of the $K$ shell is $1800$ units. Therefore,the energy of the $K_\alpha$ line is equal to ...... units.

$(a)$ An $X$-ray tube produces a continuous spectrum of radiation with its short wavelength end at $0.45\,\mathring{A}$. What is the maximum energy of a photon in the radiation?
$(b)$ From your answer to $(a)$,guess what order of accelerating voltage (for electrons) is required in such a tube?

The potential difference applied to an $X$-ray tube is increased. As a result,in the emitted radiation

The potential difference applied to an $X-$ray tube is increased. As a result,in the emitted radiation: