The figure shows Moseley's plot between $\sqrt{f}$ and $Z$, where $f$ is the frequency and $Z$ is th

Question

The figure shows Moseley's plot between $\sqrt{f}$ and $Z$, where $f$ is the frequency and $Z$ is the atomic number. Three lines $A, B$ and $C$ shown in the graph may represent

Professor PC Thomas Classes · Answer

Moseley's Law is given by: $\sqrt{f} = a(Z - b)$ where $a$ is the slope and $b$ is the $x$-intercept (the screening constant). The Graph: Displays three lines ($A$, $B$, $C$) with increasing intercepts ($b_A < b_B < b_C$) and decreasing slopes ($a_A > a_B > a_C$). Why Options A & B are wrong: Lines from the same series (e.g., $K_\alpha, K_\beta, K_\gamma$) share the same screening constant ($b \approx 1$). If these options were correct, all three lines would originate from the exact same point on the $Z$-axis. Why Option C is right: Lines from different series ($K_\alpha, L_\alpha, M_\alpha$) have increasing intercepts ($b_K < b_L < b_M$) and decreasing slopes ($a_K > a_L > a_M$). This perfectly matches the visual behavior of lines $A$, $B$, and $C$. The Verdict: The provided solution (D) is incorrect. The physically accurate answer is Option C.