Answer
a) Stopping voltage $= 4.23V$
b)$K_{max} = 4.23eV$
c)Electron speed = $1.21\times 10^{6}m/s$
Work Step by Step
It may actually prove easier to find the most energetic kinetic energy, then the stopping voltage, for reasons that should become clear in a moment.
$K = \frac{hc}{190nm} - 2.3eV = \frac{1240eV-nm}{190nm}-2.3eV$
b)$= 4.23eV$
The stopping voltage is just the voltage required to stop an electron with this, the maximum kinetic energy.
a)$\frac{4.23eV}{e} = 4.23V$
Assuming that this electron's speed is nonrelativistic ($v
