The wavelength of $X-$rays is

What is the difference between soft and hard $X-$rays?

The wavelength of $X$-rays is of the order of ...... $ \mathring A $.

Electrons of mass $m$ with de-Broglie wavelength $\lambda$ fall on a target. The cut-off wavelength $\lambda_0$ is equal to [$h=$ Planck's constant,$c=$ velocity of light].

If the minimum wavelength obtained in an $X-ray$ tube is $2.5 \times 10^{-10} \ m$,the operating potential of the tube will be.....$kV$.

When $X$-rays of wavelength $0.5 \, Å$ pass through an $Al$ sheet of thickness $10 \, mm$, their intensity is reduced to one-sixth of its initial value. The absorption coefficient for aluminum is ............. $mm^{-1}$.