The minimum wavelength of $X$-rays produced in a Coolidge tube operating at $40 \ kV$ is ..... $\mathring A$.

An electron beam is accelerated by a potential difference $V$ to hit a metallic target to produce $X$-rays. It produces continuous as well as characteristic $X$-rays. If $\lambda_{\min}$ is the smallest possible wavelength of $X$-ray in the spectrum,the variation of $\log \lambda_{\min}$ with $\log V$ is correctly represented in:

When are characteristic $X$-ray emissions produced?

The variation of wavelength $\lambda$ of the $K_{\alpha}$ line with atomic number $Z$ of the target is shown by the following curve of

If the cathode-anode potential difference in an $X$-ray tube is $10^5 V$,then the maximum energy of an $X$-ray photon can be:

$A$ charged gold leaf electroscope has its leaves apart by a certain amount with enclosed air. When the electroscope is subjected to $X$-rays,then the leaves