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

$X$-rays which can penetrate through longer distances in substances are called

Which one of the following statements is $WRONG$ in the context of $X$-rays generated from an $X$-ray tube?

$\Delta \lambda$ is the difference between the wavelength of the $K_\alpha$ line and the minimum wavelength of the continuous $X$-ray spectrum when the $X$-ray tube is operated at a voltage $V$. If the operating voltage is changed to $V / 3$,then the above difference is $\Delta \lambda^{\prime}$. Then:

The structure of solid crystals is investigated by using

When a metal target is bombarded with high-energy electrons,the electromagnetic waves generated are