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Photon Energy Formula (E = hf)

E = h·f

What it means

The energy of a single photon is Planck's constant times its frequency — a cornerstone of quantum physics.

Variables

SymbolQuantitySI unit
EenergyJ
hPlanck constantJ·s
ffrequencyHz

Worked example

Given h = 6.6260e-34 J·s, f = 5.0000e+14 Hz, solve for E:

E = 3.3130e-19 J

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