Answer
(a) $80.6KeV$
(b) $80.6KV$
Work Step by Step
(a) We know that
$K_{min}=|E_k|=13.6\frac{(78-1)^2}{1}eV$
$\implies K_{min}=(13.6)(77)^2$
$K_{min}=80.6KeV$
(b) We know that
$K=Ve$
This can be rearranged as:
$V=\frac{K}{e}$
We plug in the known values to obtain:
$V=\frac{80.6\times 1.6\times 10^{-19}}{1.6\times 10^{-19}}$
$V=80.6KV$
