Given, φ=3.5eV and V0=−1.2V By the Einstein's photoelectric equation hv=φ0+eV0 ⇒hv=(3.5eV−1.2eV)=2.3eV Hence, energy of incident photon is 2.3eV. If the higher frequency photons are used, photoelectric current remains unchanged and photoelectric current will be maximum. If the intensity of the incident light increases.