why photoelectric current shows varying graph with frequency?

Na'ira Farooqi

The greater the energy, the larger the frequency and the shorter (smaller) the wavelength of light. Electrons can only be ejected from atoms when the energy the atom receives from the incoming electron is above the THRESHOLD FREQUENCY for that particular metal. So if you draw a graph or current against frequency, you will get NO CURRENT when the frequency is below the THRESHOLD FREQUENCY, then you will get current when the frequency rises above that.
More INTENSITY means more photons of the same energy per second. So increasing the INTENSITY for frequency BELOW the THRESHOLD FRQCY will make not difference (no electrons will come out), but increasing INTENSITY for frequency ABOVE the THRESHOLD FRQCY will increase the number of electrons released, and will therefore increase the current.
Ta daaaa!

Tabitha Farrant