In a photoelectric experiment, electrons are ejected from metal X and Y by light of intensity I and frequency f The potential difference V required to stop the electrons is measured for various frequencies. If Y has a greater work function than which one of the following graphs best illustrates the expected results?

According to Einstein photoelectric effect formula, we have 

$hf=\varphi +eV$, where $\varphi$ is the work functional of metal.

Work function of a metal is defined as the minimum energy required to eject an electron from its surface with zero kinetic energy.

According to question,

${\varphi }_Y>{\varphi }_X$

${\left(h{f}_0\right)}_Y>{\left(h{f}_0\right)}_X$

[f0 = Threshold frequency]

Hence, graph with higher threshold frequency for Y is the correct option.