The K_β X-rays from certain elements are provided below. Element Ne...

According to Moseley's law, the frequency $\nu$ of the emitted X-ray is related to the atomic number $Z$ by the equation:

$\sqrt{\nu} = a(Z - b)$

where $a$ is a proportionality constant and $b$ is the screening constant.

For $K_\beta$ radiation, the transition occurs from the M shell ($n=3$) to the K shell ($n=1$). The screening constant $b$ for the K-series is a positive value.

The equation represents a straight line when $\sqrt{\nu}$ is plotted against $Z$.

At the $Z$-intercept, $\sqrt{\nu} = 0$, which gives $Z = b$.

Since $b > 0$, the graph is a straight line with a positive $Z$-intercept.