# Paul Dirac

## Electromagnetic spectrum

- 1 nanometre = 10
^{-9} metres
- Speed of light = roughly 3 x10
^{8} metres/sec
- Frequency = (speed of light)/(wavelength)
- Plank's constant = 6.626 x10
^{-34} Joule seconds

for light of wavelenth 500 nanometres,

1 quantum = 6.626 x10^{-34}x3 x10^{8}/(500x10^{-9}), roughly 4x10^{-19} Joules