#### Answer

$K = 75~eV$

#### Work Step by Step

The initial kinetic energy of the proton must be equal in magnitude to the energy lost after passing through a potential difference of $75~V$
We can find the initial kinetic energy of the proton:
$K = \Delta V~q$
$K = (75~V)(1.6\times 10^{-19}~C)$
$K = 1.20\times 10^{-17}~J$
$K = (1.20\times 10^{-17}~J)(\frac{1~eV}{1.6\times 10^{-19}~J})$
$K = 75~eV$