CBSE Class 12 · 2006 · Modern PhysicsShort Answer

Threshold frequency ${\nu }_0$: the minimum frequency of incident light that can just cause photoemission; below it no electrons are emitted.
Stopping potential $V_0$: the minimum retarding potential at which the photoelectric current becomes zero; $e{V}_0=K_{max}$.
(i) Increasing the frequency (intensity fixed) does not change the saturation photocurrent — the number of emitted electrons depends on the number of photons, not their energy (it only raises $K_{max}$).
(ii) Increasing the intensity (frequency fixed) increases the photocurrent, because more photons arrive per second and eject proportionally more electrons.