Home
Class 12
PHYSICS
Two polaroids, P(1)andP(2) are set-up so...

Two polaroids, `P_(1)andP_(2)` are set-up so that their pass-axis crossed with respect to each other. A third polaroids, `P_(3)` is now introduces between these two so that its pass-axis makes and anlge `theta` with the pass-axis of `P_(1)`.
A beam of unpolarised light, of intensity I, is incident on `P_(1)`. If the intensity of light, that gets transmitted through this combination of three polaroids is I find the ratio `((I)/(I))` when `theta` equals.
`(i) 30^(@)" "(ii)45^(@)`

Text Solution

Verified by Experts

`ItoP_(1)toP_(3)toP_(2)toI`
Angle between `P_(1)andP_(3)=0`
So, angle between `P_(2)andP_(3)=90-0`.
Now, intensity of light after crossing `P_(1)` will be `(I)/(2)`
Intensity after `P_(3):=((I)/(2))cos^(2)theta`
Intensity after `P_(2):=((I)/(2)cos^(2)theta)cos^(2)(90-theta)impliesI=(I^(2))/(4)cos^(2)thetasin^(2)theta`
So, `(I)/(I)=((I^(2))/(4)cos^(2)thetasin^(2)theta)+I`
`=(cos^(2)thetasin^(2)theta)/(4)`
For `theta=30^(@)" "(I)/(I)=(cos^(2)30sin^(2)30)/(4)=(3)/(64)`
For `theta=45^(@)," "(I)/(I)=(3)/(32)`.
Promotional Banner

Topper's Solved these Questions

  • XII BOARDS

    XII BOARDS PREVIOUS YEAR|Exercise SECTIONS-D|4 Videos

  • XII BOARDS

    XII BOARDS PREVIOUS YEAR|Exercise SECTIONS-E|4 Videos

  • XII BOARDS

    XII BOARDS PREVIOUS YEAR|Exercise SECTIONS-B|6 Videos

  • SAMPLE PAPER 2019

    XII BOARDS PREVIOUS YEAR|Exercise SECTION D|6 Videos

Similar Questions

Explore conceptually related problems

Unpolarised light of intensity I is incidnet of the polaroid. What will be the intensity of light transmitted by the polaroid?

Two polaroids are placed such that their planes are parallel to each other with their access of transmission at 30°. If an unpolarised light of intensity I_0 is incident on first polaroid polarizer then intensity of light that will be transmitted through the second polaroid is

A system of three polarizers P_(1),P_(2),P_(3) is set up such that the pass axis of P_(3) is crossed with respect to that of P_(1) . The pass axis of P_(2) is incined at 60^(@) to the pass axis of P_(3) . When a beam of unpolarized light of intensity I_(0) is incident on P_(1) the intensity of light transmitted by the three polarizes is I.The ratio (I_(0)//I) equals (nearly):

Two polaroids with their principal sections aligned at 60^@ , are placed in the path of a beam of unpolarized light of intensity I_0 . What is the intensity of light transmitted ?

Two polaroids P_1 and P_2 are placed with their axis perpendicular to each other. Un-polarized light I_0 is incident on P_1 . A third polaroid P_3 is kept in between P_1 and P_2 such that its axis makes an angle 45^@ with that of P_1 . The intensity of transmitted light through P_2 is

An unpolarized light with intensity 2I_(0) is passed through a polaroid. The resultant intensity of the transmitted light will be

Two Polaroids P_(1) and P_(2) are placed with their axis perpendicular to eachother. Unpolarised light I_(0) is nicident on P_(1) . A third polaroid P_(3) is kept in between P_(1) and P_(2) such that its axis makes an angle 45^(@) with that of P_(1) . The intensity of transmitted light through P_(2) is

Unpolarised light of intensity I is passed through a polaroid. What is the intensity of emerging polaroised light ?