# In moseley's law $\sqrt v=a(z-b)$, the values of the screening constant for K-series and L-series of X-rays are respectively

$\begin {array} {1 1} (1)\;1,6.4 & \quad (2)\;1,4 \\ (3)\;4,6 & \quad (4)\;2,4 \end {array}$

(1) 1,6.4