what is plane polarised light
Answers
Optical isomers are named because they can rotate a plane of polarized light. Light is plane-polarized if all of the light waves are vibrating in the same, parallel, direction. This is shown below with a single wave (line) below.
Polarised light is light that vibrates in a single direction due to its passage through a polariser. Light is also made up of vibrations - this time, electromagnetic ones. Some materials have the ability to screen out all the vibrations apart from those in one plane and so produce plane polarised light.
The most familiar example of this is the material that Polaroid sunglasses are made of. If you wear one pair of Polaroid sunglasses and hold another pair up in front of them so that the glasses are held vertically rather than horizontally, you'll find that no light gets through - you will just see darkness. This is equivalent to the two slits at right angles in the string analogy. The polaroids are described as being "crossed".