Given figure shows few data points in a photo electric effect experiment for a certain metal.

(1) Graph of $V_{s}$ and $f$ given at $B(5.5,0)$

Minimum energy for ejection of electron

$=$ Work function $(\phi)$.

$\phi=h V$ joule or $\phi=\frac{h V}{e} \mathrm{eV}($ for $V=0)$

$\therefore \phi=\frac{6.62 \times 10^{-34} \times 5.5 \times 10^{14}}{1.6 \times 10^{-19}} \mathrm{eV}=2.27 \mathrm{eV}$