Question

In Moseyls law $\sqrt{v}=a(z-b)$, the value of the screening constant for $K-$series and $L-$series of $X-$series rays are respectively :

• A. $1,4$
• B. $4,6$
• C. $2,4$
• D. $1,6.4$

Answer 1

The correct option is D $1,6.4$

Moseley’s Law Statement :

The frequency of any spectral line in characteristic X-rays spectrum directly varies as the square of the atomic number of the element emitting it, or $v\propto Z^2$ .

Mathematically Moseley’s law may be written as $\sqrt{v}=a(Z-b)$. Here, $Z$ is the atomic number of the element and a and b are constants depending upon the particular line.

For K-series $b$ (called screening constant) is nearly equal to $1$. Whereas for L-series b is nearly equal to $6.4$.