The shortest wavelength of $X-$rays emitted from an $X-$ray tube depends upon

The wavelength of $K_\alpha$ $X$-rays produced in an $X$-ray tube is $0.76 \ \mathring{A}$. The atomic number of the anode material is:

The $K_{\alpha}$ $X$-ray emission line of tungsten occurs at $\lambda = 0.021 \ nm$. The energy difference between $K$ and $L$ levels in this atom is about:

In an $X$-ray tube,the wavelength of characteristic $X$-rays is a property of .......

$(a)$ 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?

If the wavelength of the $K_\alpha$ line of Molybdenum (atomic number $Z = 42$) is $0.7078\, \mathring A$,then the wavelength of the $K_\alpha$ line of Zinc (atomic number $Z = 30$) is .......