Og-3 Interference colours in Mica (Polarisation)
Published: Wednesday 15 March 2006 - Updated: Monday 28 March 2011
Aim
To demonstrate interference colours in mica sheet.
Apparatus
- Overhead projector
- Mica sheet
- Polaroids
Diagrams
Click on pictures to enlarge.
Description
Mica is birefringent. The cleavage planes are such that an incident wave is split into two waves polarised vertically to each other. On emergence from the crystal the waves display a phase difference dependent on the thickness of the plate and the wavelength. These two phase displaced waves interfere with each other to produce the interference colours displayed.