Arun
Last Activity: 4 Years ago
IαA
2
where A is the amplitude and I is the intensity
For unpolarised light, it can be resolved into two components of equal magnitude in any pair of perpendicular directions. So the amplitude that is along the plane of polarisation of the polaroid will always be
2A
So, the intensity which will pass through it will always be
2I0
?Now when this polarised light falls on polaroid B whose plane of polarisation makes an angle θ with the plane of polarisation of incident light, the component of amplitude along the plane of polarisation of the polaroid is Acosθ.
Therefore, intensity of light that passes through is I
i cos 2 θ where I i
is the intensity of incident light.
Here, I
i? = 2I 0
and θ=45
So intensity of light emerging through B is
2I 0? × 21? = 4I0.
