Asked by Jenay
Determine the intensity of light passing through a polarizer-analyzer combination with an angle of 45° between them.
Answers
Answered by
bobpursley
assume the incoming light is coming an at an angle theta to the first filter, and assume it is not circular polarization.
light getting through
I*costheta
now the light getting thru the second filter is
I*cosTheta*cos(theta+45)
now if I remember my trig identities that equals
I*(cosTheta(cos(theta)cos45-sinThetasin45)=
I(cos^2theta*cos45-cosTheta*sinTheta*sin45)=
I(.707)(cos^2Theta -cosTheta*SinTheta)=
Now, comparing that to the original incident light, it depends on the incident angle with the first plate. If Theta is zero, then .707 gets thru. If Theta is 90 deg, zero gets thru. You can see the graph here.
http://www.wolframalpha.com/input/?i=plot+y-%3D.707((cos(x)*cos(x)-sin(x)*cos(x))
light getting through
I*costheta
now the light getting thru the second filter is
I*cosTheta*cos(theta+45)
now if I remember my trig identities that equals
I*(cosTheta(cos(theta)cos45-sinThetasin45)=
I(cos^2theta*cos45-cosTheta*sinTheta*sin45)=
I(.707)(cos^2Theta -cosTheta*SinTheta)=
Now, comparing that to the original incident light, it depends on the incident angle with the first plate. If Theta is zero, then .707 gets thru. If Theta is 90 deg, zero gets thru. You can see the graph here.
http://www.wolframalpha.com/input/?i=plot+y-%3D.707((cos(x)*cos(x)-sin(x)*cos(x))
There are no AI answers yet. The ability to request AI answers is coming soon!
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.