Question

According to Moseley’s law, the frequency of a spectral line in X-ray spectrum varies as

• A. Atomic number of the element
• B. Square of atomic number of the element
• C. Square root of atomic number of the element
• D. Fourth power of atomic number of the element

Answer 1

The correct option is B Square of atomic number of the element

$\sqrt{\nu }=a(Z-b)$
where, a and b are constants depends on type of line (i.e. K,L,etc.) in X-ray.
$\nu =a^2(Z-b{)}^2$
frequency $\propto$ square of atomic No.

So, the answer is option (B).