Question 40.38: Here are the Kα wavelengths of a few elements: Make a Mosele......

From the data given in the problem, we calculate frequencies (using Eq. 38-1), take their square roots, look up the atomic numbers (see Appendix F), and do a least-squares fit to find the slope: the result is 5.02 × 10$^7$ with the odd-sounding unit of a square root of a hertz. We remark that the least squares procedure also returns a value for the y-intercept of this statistically determined “best-fit” line; that result is negative and would appear on a graph like Fig. 40-17 to be at about – 0.06 on the vertical axis. Also, we can estimate the slope of the Moseley line shown in Fig. 40-17:

$f=\frac{c}{\lambda} .$          (38-1)

$\frac{(1.95-0.50) 10^9  Hz ^{1 / 2}}{40-11} \approx 5.0 \times 10^7  Hz ^{1 / 2}$