I have some doubts concerning Polarized light and have read some of the other threads on this issue but wasn't quite convinced with the explanation mentioned therein so I've tried to articulate my doubts etc., and let me know if I am way off track.
The specific example I am alluding to is on page 236 of TBR Physics part 2, example 10.2a. In the example, a vertical polarized light is sent through an empty sample cell first and it then falls on a horizontally oriented polarizer. So nothing comes through out of the polarizer. Next the sample cell is filled with D glucose and one quarter of incident light intensity gets through. This example uses Malu's law which is I = I(original)Cos^2theta where I is the intensity of light coming out of polarizer and I(original) is the intensity of incident light and theta is the angle of incident light to polarizer.
So using Malu's law they've calculated that incident light should be at a 60 deg angle to the polarizer, in which case 25% of it will fall through the polarizer. So therefore, the D glucose must be rotating the Vertically polarized light by 30 deg. And all of that makes sense to me.
What confuses me is this. So if an unpolarized light incident at 30 deg angle to the polarizer will pass through with 75% intensity -- at 45 deg angle will pass through with 50% intensity -- at 60 deg will pass through with 25% intensity -- at 90 deg will not pass through. So the idea that polarizer allows light vibrating in just 1 plane (parallel to the plane of polarization) does not hold. It will allow all planes at varying intensity except the one which is oriented perpendicular to the plane of polarization. And the maximum intensity will be for the one which is parallel to the plane of polarization. Is that correct?
OR do the molecules in the polarizer take that 60 deg incident light, rotate 25% of that light intensity by 60 deg and out comes 25% intensity but rotating only in the plane of the polarizer?
The specific example I am alluding to is on page 236 of TBR Physics part 2, example 10.2a. In the example, a vertical polarized light is sent through an empty sample cell first and it then falls on a horizontally oriented polarizer. So nothing comes through out of the polarizer. Next the sample cell is filled with D glucose and one quarter of incident light intensity gets through. This example uses Malu's law which is I = I(original)Cos^2theta where I is the intensity of light coming out of polarizer and I(original) is the intensity of incident light and theta is the angle of incident light to polarizer.
So using Malu's law they've calculated that incident light should be at a 60 deg angle to the polarizer, in which case 25% of it will fall through the polarizer. So therefore, the D glucose must be rotating the Vertically polarized light by 30 deg. And all of that makes sense to me.
What confuses me is this. So if an unpolarized light incident at 30 deg angle to the polarizer will pass through with 75% intensity -- at 45 deg angle will pass through with 50% intensity -- at 60 deg will pass through with 25% intensity -- at 90 deg will not pass through. So the idea that polarizer allows light vibrating in just 1 plane (parallel to the plane of polarization) does not hold. It will allow all planes at varying intensity except the one which is oriented perpendicular to the plane of polarization. And the maximum intensity will be for the one which is parallel to the plane of polarization. Is that correct?
OR do the molecules in the polarizer take that 60 deg incident light, rotate 25% of that light intensity by 60 deg and out comes 25% intensity but rotating only in the plane of the polarizer?
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