The continuous part of $X$-ray spectrum is a result of the

An $X$-ray tube has a short wavelength limit at $0.45 \mathring{A}$. The voltage of the tube is ........ $V$.

$\Delta \lambda$ 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 solids is investigated by using

For hard $X$-rays,which of the following is true?

The potential difference applied to an $X$-ray tube is $5 \text{ kV}$ and the current through it is $3.2 \text{ mA}$. Then the number of electrons striking the target per second is