Key Observations on Photoelectric Effect

The photoelectric effect exemplifies the particle nature of light. 

Based on conservation of energy, no photoelectron can have energy more than that of an incident photon. 

The energy of the photoelectrons is always less than that of the incident photons, because some energy (work function) is required to break the electrons loose. 

The maximum energy of the photoelectrons is independent of the intensity of the incident light. 

Electrons are not ejected no matter how high the intensity of the incident light is, unless the incident light has the energy corresponding to the threshold frequency characteristic of a particular metal. 

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