Tag: wave optics

Questions Related to wave optics

Through which character we can distnguish the light waves from sound waves.

polarisation of light polarisation wave optics optics physics

  1. Interference

  2. Refraction

  3. Polarisation

  4. Reflection

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Correct Option: A

In the propagation of light waves, the angle between the direction of vibration and plane of polarization is :

polarisation of light polarisation wave optics optics physics

  1. $0^{ \circ }$

  2. $90^{ \circ }$

  3. $45^{ \circ }$

  4. $80^{ \circ }$

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Correct Option: C

A stretched string is 1 m long. Its mass per unit length is 0.5 g/m. It is stretched with a force of 20 N. It plucked at a distance of 25 cm from one end. The frequency of note emitted by it will be:

polarisation of light polarisation wave optics optics physics

  1. $400 Hz$

  2. $300 Hz$

  3. $200 Hz$

  4. $100 Hz$

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Correct Option: C

Which of the following cannot be polarised

polarisation of light polarisation wave optics optics physics

  1. Radio waves

  2. UV rays

  3. IR rays

  4. Ultrasonic waves

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Correct Option: D

A beam of light strikes a piece of glass at an angle of incidence of $60 ^ { \circ }$ and the reflected beam is completely Plane polarised. Find the refractive index of this glass

polarisation of light polarisation wave optics optics physics

  1. $\sqrt { 2 }$

  2. $\sqrt { 3 / 2 }$

  3. $\sqrt { 3 }$

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

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Correct Option: C

If the polarizing angle for a given medium is $60^{\circ}$, then the refractive index of the medium is 

polarisation of light polarisation wave optics optics physics

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

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

  3. 2

  4. $\sqrt{3}$

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Correct Option: D

A polarizer and an analyzer are arranged with their optic axes parallel to each other Symmetric light first passes through the polarizer and then the analyzer and the intensity of the light emerging is 'I'. If the analyzer is turned through $30^o$, the percent changes in the intensity is

polarisation of light polarisation wave optics optics physics

  1. $75\%$

  2. $50\%$

  3. $25\%$

  4. $40\%$

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Correct Option: C

When unpolarized light beams are incidents in the air into glass ($n=1.5$ at polarising angle)

polarisation of light polarisation wave optics optics physics

  1. reflected beams is $100$ polarised

  2. reflect and refracted beams are partially polarised

  3. the reason for (a) is that almost all the light is reflected

  4. all the above

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Correct Option: A
Explanation:

When unpolarized light is incident at Brewster angle from one medium to another, the light that is reflected from the surface is perfectly polarized

Dichorism means

polarisation of light polarisation wave optics optics physics

  1. selective absorption of unpolarised light.

  2. selective absorption of dispersed light.

  3. selective absorption of scattered light.

  4. selective absorption of one of the polarised component.

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Correct Option: D
Explanation:

Dichromism is the selective absorption of one orthogonal polarization component of an incident beam over the other. this phenomenon is due to anisotropy of the material, with one polarization component experiencing preferential absorption.

From Brewster's law, it follows that the angle of polarization depends upon

polarisation of light polarisation wave optics optics physics

  1. the wavelength of light

  2. orientation of the plane of polarization

  3. orientation of the plane of vibration

  4. none of these

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Correct Option: A
Explanation:

$\theta _B=tan^{-1}\dfrac{n _2}{n _1}$

Since the refractive index for a given medium changes depending on the wavelength of light, Brewster's angle will also vary with wavelength.