For harder $X$-rays:

If $f_1, f_2$,and $f_3$ are the frequencies of $K_\alpha, K_\beta$,and $L_\alpha$ $X$-rays of a given metal,respectively,then:

If the wavelength of the $K_\alpha$ line of an element with atomic number $43$ is $\lambda$,then the wavelength of the $K_\alpha$ line of an element with atomic number $29$ is:

Assertion : Soft and hard $X-$ rays differ in frequency as well as velocity.
Reason : The penetrating power of hard $X-$ rays is more than the penetrating power of soft $X-$ rays.

What does the $K\alpha$ characteristic $X$-ray represent?

The wavelength of $X$-rays decreases,when