When radiation falls on plate C, the ammeter reading remains zero till jockey is moved from the end P to the middle point of the wire PQ. Therefore the deflection is recorded in the ammeter. The maximum kinetic energy of the emitted electron is :

Question

$\begin {array} {1 1} (a)\;2\: eV & \quad (b)\;4\: eV \\ (c)\;8\: eV& \quad (d)\;10\: eV \end {array}$