Tag: polarisation of light

Questions Related to polarisation of light

Two nicol prisms A and B are placed in the path of a beam of unpolarised light, so that no light emerges out of B. In between these two, a third nicol C is placed such that its principal section is at an angle of $30^0$ with that of A. The percentage of intensity of incident unpolarised light that emerges from B.

  1. $2.8$

  2. $9.4$

  3. $15.3$

  4. $10.2$


Correct Option: C

Two polaroids are placed in the path of unpolarized beam of intensity ${I _0}$ such that no light is emitted from the secong polaroid. If a third polaroid whose polarization axis makes an angle $\theta $ with the polarization axis of first polaroid, is placed between these polaroids then the intensity of light emerging from the last polaroid will be

  1. $\left( {\frac{{{I _0}}}{8}} \right){\sin ^2}2\theta $

  2. $\left( {\frac{{{I _0}}}{4}} \right){\sin ^2}2\theta $

  3. $\left( {\frac{{{I _0}}}{2}} \right){\sin ^2}2\theta $

  4. ${I _0}{\cos ^4}2\theta $


Correct Option: A

Unpolarized light is incident on a planet sheet of water surface. The angle of incident for which the reflected and refracted rays are perpendicular to each other is $\left(\mu _{water}=\dfrac{4}{3}\right)$.

  1. $\sin^{-1}\left(\dfrac{4}{3}\right)$

  2. $\tan^{-1}\left(\dfrac{3}{4}\right)$

  3. $\tan^{-1}\left(\dfrac{4}{3}\right)$

  4. $\sin^{-1}\left(\dfrac{1}{3}\right)$


Correct Option: C

A polariser is used to :

  1. Reduced intensity of light

  2. Produced polarised light

  3. Increases intensity of light

  4. Produced unpolarised light


Correct Option: B

Which inert gas possesses the highest polarizability ? 

  1. He

  2. Ne

  3. Ar

  4. Xe


Correct Option: D

Two liner polarizers are crossed at an angle of ${ 60 }^{ \circ  }$. The fraction of intensity of light transmitted by the pair is

  1. $\dfrac { 1 }{ 4 } $

  2. $\dfrac { 1 }{ 8 } $

  3. $\dfrac { 3 }{ 8 } $

  4. $\dfrac { 1 }{ 2 } $


Correct Option: A

A polaroid making an angle ${ 60 }^{ \circ  }$ with electric vector then intensity reduced by a factor of:-

  1. $\dfrac { 1 }{ 4 } $

  2. $\dfrac { 3}{ 4 } $

  3. $\dfrac { 1 }{ 2 } $

  4. $\dfrac { 1 }{ 3} $


Correct Option: A

Two polaroids are placed in the path of unpolarized beam of intensity ${ I } _{ 0 }$ such that no light is emitted from the second polaroid. if  a third polaroid whose polarization axis makes an angle $\theta $ with the polarization axis of first polaroid is plcaed between these polaroids then the intensity of light emerging from the last polaroid is 

  1. $\left( \frac { { I } _{ 0 } }{ 8 } \right) { sin }^{ 2 }2\theta $

  2. $\left( \frac { { I } _{ 0 } }{ 4 } \right) { sin }^{ 2 }2\theta $

  3. $\left( \frac { { I } _{ 0 } }{ 4 } \right) { cos }^{ 4 }\theta $

  4. ${ I } _{ 0 }{ Cos }^{ 4 }\theta $


Correct Option: A

Two polaroids are placed in the path of unpolarized beam of intensity $I _ { 0 }$ such that no light is emitted from the second Polaroid. If a third Polaroid whose polarization axis makes an angle $\theta$ with the polarization axis of first polaroid, is placed between these polaroids then the intensity of light emerging from the last polarids will be :

  1. $\left( \dfrac { I _ { 0 } } { 8 } \right) \sin ^ { 2 } 2 \theta$

  2. $\left( \dfrac { I _ { 0 } } { 4 } \right) \sin ^ { 2 } 2 \theta$

  3. $\left( \dfrac { I _ { 0 } } { 2 } \right) \cos ^ { 4 } \theta$

  4. $I _ { 0 } \cos ^ { 4 } \theta$


Correct Option: A

Which of the following is not an anisotropic?

  1. zinc blend

  2. quartz

  3. sapphire

  4. iron oxide

  5. apatite


Correct Option: A
Explanation:
Anisotropy is the property of being directionally dependent, which implies different properties in different directions.
Zinc blend (ZnS) is the only isotropic material in the list.
Quartz crystals and Saphire are birefringent, so they exhibit optical anisotropy.