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Multiple choice polarisation of light polarisation wave optics optics physics

Optically active substances are those which

  1. produce polarized light

  2. rotate the plane of polarization of the polarized light.

  3. produce double refraction

  4. convert a plane polarized light into circularly polarized light.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Optically active substance by definition are substances which can rotate the plane of polarization of polarized light.


Answer. B) rotate the plane of polarization of polarized light.

Multiple choice polarisation of light polarisation wave optics optics physics

If for a calcite crystal, $\displaystyle\mu _0$ and $\displaystyle\mu _e$ are the refractive indices of the crystal for O-ray and E-ray repectively, then along the optic axis of the crystal

  1. $\displaystyle\mu _0$ = $\displaystyle\mu _e$

  2. $\displaystyle\mu _0$ > $\displaystyle\mu _e$

  3. $\displaystyle\mu _0$ < $\displaystyle\mu _e$

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In calcite crystal, only along the optical axis, the refractive indices of the crystal are equal for O-ray and E-ray

Multiple choice polarisation of light polarisation wave optics optics physics

Optically active substances are those substances which 

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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

Multiple choice polarisation of light polarisation wave optics optics physics

Polaroid glass is used in sun glasses because

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice polarisation of light polarisation wave optics optics physics

A nicol prism is based on action of

  1. refraction

  2. double refraction

  3. dichroism

  4. both (b) and (c)
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

Multiple choice polarisation of light polarisation wave optics optics physics

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.

  1. 1

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

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

  4. $\dfrac{1}{2\sqrt 2}$
Reveal answer Fill a bubble to check yourself
B Correct answer
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 $
Multiple choice polarisation of light polarisation wave optics optics physics

A Nicol prism can be used.

  1. For producing and analysing polarised light

  2. Only to analyse polarized light

  3. Only to produce polarized light

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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

Multiple choice polarisation of light polarisation wave optics optics physics

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

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

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

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

  4. $\tan ^ { - 1 } ( n )$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Brewster's law states that the angle of incidence i for which reflected light is totally polarized is given by tan(i) = n, where n is the refractive index.

Multiple choice physics thermal physics heat and heat transfer transfer of heat fundamentals of heat transfer

A person takes hot tea by pouring it into the saucer (plate) when one is in a hurry because he knows that

  1. The latent heat of steam is high and the tea will become cold quickly

  2. The evaporation increases with the increase in surface area and cooling of tea is faster

  3. Part of heat will be absorbed by the saucer (plate) and the tea will become cold quickly

  4. The high specific heat of water makes the tea cold quickly
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Evaporation is a surface phenomenon. By pouring tea into a saucer, the surface area exposed to the air increases, which significantly accelerates the rate of evaporation and consequently cools the liquid faster.