The structure of solids is investigated by using

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

An $X$-ray tube operates at $50 \, kV$ and $20 \, mA$. The target material has a mass of $1.0 \, kg$ and a specific heat capacity of $495 \, J \cdot kg^{-1} \cdot ^\circ C^{-1}$. One percent of the applied electrical power is converted into $X$-rays,and the remaining energy is used to heat the target. Then:
$(1)$ $A$ suitable target material should have a high melting point.
$(2)$ $A$ suitable target material should have low thermal conductivity.
$(3)$ The rate of rise of temperature of the target is $2 \, ^\circ C/s$.
$(4)$ The minimum wavelength of the emitted $X$-rays is $0.25 \, \mathring{A}$.

An $X$-ray tube is operated at $1.24$ million volts. The shortest wavelength of the produced photon will be ..... $nm$.

If the operating potential of an $X-$ray tube is $50 \text{ kV}$,the velocity of $X-$rays coming out of it is

The minimum wavelength of $X$-rays produced in a Coolidge tube operated at a potential difference of $40 \ kV$ is ....... $\mathring{A}$.