Module Questions

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Nhi Vo 3A
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Joined: Sat Jul 09, 2016 3:00 am

Module Questions

Postby Nhi Vo 3A » Thu Oct 06, 2016 2:52 pm

When the energy per photon is equal to the energy required to remove an electron, what is this energy called?

Is the answer threshold energy?

Also, if long wavelength light is not ejecting electrons from a metal surface will increasing the intensity of the light result in electrons being ejected?

Thank you

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Joined: Fri Jul 15, 2016 3:00 am

Re: Module Questions

Postby Jeannie_Kim_1I » Thu Oct 06, 2016 4:12 pm

The energy required to release an electron is the threshold energy. When the energy of a photon is equal to the threshold energy, an electron will initially be released and will drift towards the electron detector due to the electrostatic attraction between the slightly positively charged detector and the negatively charged electron, but after a short while, the electron will return back to the metal surface. The electron will be fully released only when the photon energy exceeds the threshold energy.

Increasing the intensity of the light means increasing the number of photons, but each individual photon needs enough energy to interact with one atom of the metal to release one electron; this is why increasing the intensity doesn't increase electron release. The energy of a photon is determined by its frequency. The shorter the wavelength, the higher frequency, and the higher the energy.

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