The mass of zinc produced by the electrolysis of zinc sulphate...

Given, t = $15$min

${Zn}^{+ 2} + 2{e}^{-} ⟶ Zn$

Quantity of charge passed (Q) =Current in amperes ×Time in seconds.
=$( 0 . 015A ) \times ( 15 \times 60 ) s = 13 . 5C$

Gram equivalent mass of zinc = $\dfrac{65 . 4}{2} = 32 . 7$g
Now,  $96500$ C of charge deposit zinc =$32 . 7$ g
$13 . 5$ C charge will deposit zinc = $\dfrac{( 32 . 7g )}{( 96500C )} \times ( 13 . 5C ) = 4 . 57 \times {10}^{- 3}g$

$= 45 . 75 \times {10}^{- 4}gm$