Work Function Question

[Catherine Bubser 2C]

When solving for kinetic energy, will the work function be added or subtracted based on if absorption or emission is occurring or is it always E= hv - work?

[Chem_Mod]

You use the work function with photoelectric problems, not with absorption/emission spectra. The equation for photoelectric problems is
energy of incoming light-work function= kinetic energy

[Shivani Sakthi 1l]

The work function equation concerns the photoelectric effect which functions under the following principles:
1. no electrons can be ejected unless the initial energy of the radiation has a frequency above the threshold energy, or minimum energy required to eject electrons from metal.
2. regardless of how low intensity the radiation is, electrons are ejected immediately.
3. the kinetic energy of electrons that are ejected increases linearly with the frequency of the incident radiation
4. if the energy of the photon is less than the threshold energy, the electron is not ejected regardless of it's intensity. However, if the energy of the photon is greater than the threshold energy/work function, electrons are ejected with kinetic energy.

Taking into account these underlying principles, the equation becomes Energy of photon or hV= threshold energy/workfunction + kinetic energy.
So when solving for kinetic energy, the work function will be subtracted from the energy of the photon. If it helps, the kinetic energy equation is also KE=1/2 mv^2 . I hope this helped!

[Sarah Hong 2K]

When solving for kinetic energy, you will subtract the work function (threshold energy) to the energy of the photon (E=hV).

[Chem_Mod]

Hello Catherine,

Please refer to the following equality for all photoelectric scenarios: .