Question

Define malus law of polarization in mathematical form.

Answer 1

When a plane polarised light beam from a polariser is incident on analyser, the intensity of light emerging from analyser varies as square of cosine of angle between the planes of transmission, polarising direction of analyser nd polariser.
The intensity of light emerging from analyser is given by_


I= k ( a cos theta) 2
I= ka2 cos2 theta = I. Cos2 theta


Where I. (=ka2) is intensity of plane polarised light incident on analyser k being the proportionality constant. Thus_

I proportional cos2 theta

This is malus law...

Answer 2

$\underline \bold {Solution:-}$

According to Malus law, the intensity of linearly polarized light transmitted through a analyser is directly proportional to the square of cosine of angle between transmitting plane of polarization analyser.

Let, plane polarised light of intensity I* falls on a analyser which is tilted by ¢ from the transmitting plane of polariser . Then the projected amplitude acos¢ will only pass through it and the component asin¢ being perpendicular will be stopped.

Intensity of transmitted light I = I* cos^2 ¢