Tag: conditions for a light ray to pass undeviated

Questions Related to conditions for a light ray to pass undeviated

If reflection takes place from optically denser medium, the change in phase is

conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

  1. zero

  2. $\pi$

  3. $\pi / 2$

  4. $\pi / 3$

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Correct Option: B

A 5 cm thick glass slab is silvered at one of the surface to form a plane mirror. A point object is placed at a distance of $20cm $ from the unsilvered face. The image distance from the unsilvered face will be [R.I. of glass =1.5]

conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

  1. 26.67cm

  2. $\frac {70}{3}$

  3. 20cm

  4. 25cm

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Correct Option: A

Light starting from a medium of refractive
index $  \mu  $ undergoes refraction into a medium of index $  \mu  $. If I and r stand for angle of incidence are refraction respectively :

conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

  1. $

    \frac{\sin i}{\sin r}=\frac{\mu}{\mu^{\prime}}

    $

  2. $

    \frac{\sin i}{\sin r}=\frac{\mu^{\prime}}{\mu}

    $

  3. $

    \frac{\cos i}{\cos r}=\frac{\mu^{\prime}}{\mu}

    $

  4. $

    \frac{\sin i}{\sin r}=1 / \mu \mu^{\prime}

    $

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Correct Option: A

A small object is enclosed in a sphere of solid glass  $8 cm$  in radius. It is situated  $2 cm$  from centre and is viewed from the side to which it is nearest. Where will it appear to be it  $\mu$  of glass  $= 1.5$ ?

conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

  1. $6 cm$

  2. $4 cm$

  3. $5\dfrac { 1 }{ 3 } { cm }\quad $

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

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Correct Option: A

When a light ray is refracted from one medium into another the wavelength change from $4500{ A }^{ 0 }$ to $3000{ A }^{ 0 }$ the critial angle for a ray from second medium to first medium is 

conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

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

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

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

  4. ${ tan }^{ -1 }\left( \dfrac { 2 }{ \sqrt { 5 } } \right) $

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Correct Option: A

Which of the following statements is false?

conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

  1. A plane mirror produce a magnification of +1

  2. Focal length of a plane mirror is infinite

  3. For man of height h, to see his own complete image , a mirror of height at least equal to  h is required

  4. For a ray of light, incidenting normally on a plane mirror, the angle of reflection is $ 180^0 $

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Correct Option: C

A wave has velocity $u$ in medium $P$ and velocity $2u$ in medium $Q$. If the wave is incident in medium $P$ at an angle of $30^\circ$ then the angle of refraction will be

conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

  1. $30^\circ$

  2. $45^\circ$

  3. $60^\circ$

  4. $90^\circ$

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Correct Option: D

What is the angle of incidence if a ray of light is not deviated when it enters a block of glass?

conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

  1. $30^{\circ}$

  2. $60^{\circ}$

  3. $90^{\circ}$

  4. $0^{\circ}$

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Correct Option: D
Explanation:

The angle of incidence if a ray of light is not deviated when it enters a block of glass :

The angle of incidence is equal to angle of refraction only if the angle the  deviation is zero. This is practically impossible since, when light enters a medium from another medium it has to undergo refraction. So angle of minimum deviation is never zero but it can be a very small value. And angle of incidence is never equal to angle of refraction, if the light undergoes minimum deviation. But the angle of incidence is equal to the angle of emergence.

An under water swimmer looks upward at an unobstructed overcast sky. The vertex angle does the sky appear to subtend at the eye of swimmer is (critical angle for water air interface is  $C$).

conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

  1. $C$

  2. $C/2$

  3. $2 C$

  4. $3 C$

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Correct Option: C

A mark is made on the surface of a glass sphere of diameter 10 cm and refractive index 1.5 . it its viewed through the glass from a potion directly opposite . the distance of the image of the mark from the centre of the sphere will be 

conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

  1. 20 cm

  2. 17.5 cm

  3. 15 cm

  4. 22.5 cm

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Correct Option: A