The amount of energy required to eject an electron just out of the surface of metal is called work function of metal. The frequency of the light required for this purpose is called threshold frequency f0. Then we have

Φ = h f₀= hc /λ₀whereλ₀=threesold wavelength = wave length

corresponding to threshold frequency.It is clear that a frequency less than f₀ (i.e. wavelength greater than A) will be unable to produce the photo electric effect. This is the reason why photoelectric effect cannot be...

The minimum amount of energy necessary to start the emission of electrons from a metal's surfaceis known as its work function.

Intensity of Light: If a high intense light of frequency equal or greater than threshold frequency falls on the surface of matter, the photoelectric effect is caused. Since studying the impact of this factor is the focus of this research study, therefore, it would be discussed in detail however: one thing which is very clear is that the emission of electrons does not...

Since the atom of alkali metal has only one valence electron, it is lightly bound with the nucleus so that the work function of alkali metal is less than that of the other metal. So the photoelectrons are easily emitted from the surface of alkali metal with visible light. On the other hand, metals such as zinc, cadmium etc. require high energy radiation (UV light) to emit photoelectrons.