Newnes Interfacing Companion

1.3

Light

1.3.1 Light

The velocity of light waves in a vacuum is c = 2.99792458 × 10⁸ ms⁻¹

For any type of wave, including light waves:

For visible light, the frequency is of the order of 10¹⁵ Hz. Photodetectors cannot respond to such rapid changes and thus generally indicate rms or mean values of power of the radiation.

The energy of a photon depends on the frequency but is in the order of 10⁻²⁰ J. Most detectors respond to large numbers ...