When light from a mercury lamp $(=546\mathrm{.}1$ nm$)$ is incident on a particular metal surface, the stopping potential is $0\mathrm{.}960$ V$.$

$($a$)$

What is the work function $($in eV$)$ for this metal?

eV

$($b$)$

What stopping potential $($in V$)$ would be observed when using light from a red lamp $(=675\mathrm{.}0$ nm$)?$

V