Tag: optics

Questions Related to optics

Optically active substances are those substances which 

polarisation of light polarisation wave optics optics physics

  1. produces polarised light

  2. produces double refraction

  3. rotate the plane of polarisation of polarised light

  4. converts a plane polarised light into circularly polarised light

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Correct Option: C
Explanation:

By definition, optically active substances are those which can rotate the plane of polarisation of polarised light.

Polaroid glass is used in sun glasses because

polarisation of light polarisation wave optics optics physics

  1. it reduces the light intensity to half on account of polarisation

  2. it is fashoinable

  3. it has good colour

  4. it is cheaper

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Correct Option: A
Explanation:

Polaroid glass cut glare and haze by reducing the light intensity to half on account of polarisation, so that eyes are more comfortable and viewer can see better, therefore they are used in sun glasses.

A nicol prism is based on action of

polarisation of light polarisation wave optics optics physics

  1. refraction

  2. double refraction

  3. dichroism

  4. both (b) and (c)

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Correct Option: D
Explanation:

When a ray of light enters nicol prism, it splits into two plane polarised light in mutually perpendicular direction. One of this light undergoes total reflection and absorption whereas other comes out as a plane polarised light.

If a polaroid is kept in the path of an uniformly unpolarised light, the intensity of the transmitted light to the intensity of the light when the polaroid was not kept in its path is.

polarisation of light polarisation wave optics optics physics

  1. 1

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

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

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

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Correct Option: B
Explanation:
The component of the electric vector of all the electric vectors of unpolarised light in one direction only = $\dfrac {E _0}{\sqrt {2}} $
And, $I \propto E^2 \Rightarrow I = \dfrac {I _0}2 $

A Nicol prism can be used.

polarisation of light polarisation wave optics optics physics

  1. For producing and analysing polarised light

  2. Only to analyse polarized light

  3. Only to produce polarized light

  4. None of the above

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Correct Option: A
Explanation:

A Nicol prism is use to produce and analyse the polarised light.

What is used to measure doppler line broadening.

polarisation of light polarisation wave optics optics physics

  1. Polaroid

  2. Diffration grating

  3. Herapathite

  4. Plasma

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Correct Option: D

The angle of incidence at which reflected light is totally polarized form aim is :

polarisation of light polarisation wave optics optics physics

  1. $\sin ^ { - 1 } ( n )$

  2. $\sin ^ { - 1 } \left( \frac { 1 } { n } \right)$

  3. $\tan ^ { - 1 } \left( \frac { 1 } { n } \right)$

  4. $\tan ^ { - 1 } ( n )$

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Correct Option: D