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CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

Intensity (of light)

How bright light is: the number of photons arriving per second on an area. Intensity sets how many photons there are, not how much energy each carries, which depends only on frequency.

Example

Doubling the intensity of 400 nm light on sodium doubles the number of ejected electrons (the current), but the fastest still leave with the same KEmax⁡=1.32×10−19\mathrm{KE}_{\max} = 1.32\times10^{-19} J.

See alsoPhotonAmplitudePhotoelectric effect