Question 142: Waves Optics

Question

A system of three polarizers P1, P2, P3 is set up such that the pass axis of P3 is crossed with respect to that of P1.
The pass axis of P2 is inclined at 60o to the pass axis of P3. When a beam of unpolarized light of intensity I0 is
incident on P1, the intensity of light transmitted by the three polarizers is I. The ratio ($${{{I_0}} \over I}$$) equals (nearly) :

Accepted Answer

When unpolarized light of intensity I
0
passes through P
1
, then intensity
I
1
= $${{{I_0}} \over 2}$$
as we know, I = I
0
cos
2
$$	heta $$
Given that angle between P
2
& P
3
= 60
o
and
P
1
and P
3
are crossed that means angle between P
1
and P
3
is 90
o
so angle between P
1
and P
2
= 90ÃÂ° Ã¢ÂÂ 60ÃÂ° = 30ÃÂ°
I
2
= $${{{I_0}} \over 2}{\cos ^2}30^\circ $$ = $${{3{I_0}} \over 8}$$
I
3
= $${{3{I_0}} \over 8}{\cos ^2}60^\circ $$ = $${{3{I_0}} \over {32}}$$ = I
$$ 	herefore $$ $${{{I_0}} \over I}$$ = $${{{I_0}} \over {{{3{I_0}} \over {32}}}}$$ = $${{32} \over 3}$$ = 10.67

Answer

10.67

Answer

5.33

Answer

16.00

Answer

1.80

Waves Optics

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