15

Numerical Relationship between

wavelength and photon energy

wavelength and photon energy

•Inverse relationship: Smaller l means more energetic

–c = speed of light = 3.00 ´ 108 m/s

–h = Planck’s constant = 6.63 ´ 10-34 joule/s

•Note:
Joule is a unit of energy 1
Joule/second = 1 Watt

•Energy of a single photon of 0.5 mm visible light?

–Seems very small, but this is roughly the
energy it takes to chemically modify a single molecule.

•Photons from a 100 W lightbulb (assuming all 100W goes into light?)