Which of the following wavelengths falls in the $X-$ray region in $\mathring{A}$?

In producing $X$-rays,a beam of electrons accelerated by a potential difference $V$ is made to strike a metal target. For what value of $V$ will the $X$-rays have the lowest wavelength of $0.3094 \ \mathring{A}$? (in $kV$)

$A$ potential difference of $20 \, kV$ is applied across an $X-ray$ tube. The minimum wavelength of $X-rays$ generated (in $\mathring{A}$) is

In an $X-$ray experiment,what do $K_{\alpha}$ and $K_{\beta}$ denote?

When an $X$-ray tube operates at $60 \ kV$,the observed tube current is $50 \ mA$. Assuming that the total energy of the electrons is converted into heat,the rate of heat production at the anode in $cal/s$ is:

The wavelength of the most energetic $X$-rays emitted when a metal target is bombarded by $40 \ keV$ electrons is approximately ....... $\mathring{A}$. $(h = 6.62 \times 10^{-34} \ J \cdot s; 1 \ eV = 1.6 \times 10^{-19} \ J; c = 3 \times 10^8 \ m/s)$