Tag: introduction to light and mirror

Questions Related to introduction to light and mirror

A ray of light is incident on a plane mirror along a vector $\hat {i} + \hat {j} - \hat {k}$, then find the direction of reflected ray if normal is $\hat i + \hat j$

evs magic with mirrors image of an extended object formed by a plane mirror reflection at plane surface introduction to light and mirror

  1. $\hat {i} + \hat {j} - \hat {k}$

  2. $-\hat {i} + \hat {j} - \hat {k}$

  3. $-\hat {i} - \hat {j} - \hat {k}$

  4. $\hat {i} + \hat {j} + \hat {k}$

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Correct Option: C

When you see reflection of your own in the surface of water, Choose the correct option

evs magic with mirrors image of an extended object formed by a plane mirror reflection at plane surface introduction to light and mirror

  1. The image formed is real

  2. The image formed is inverted

  3. The image formed is erect

  4. None of the above

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Correct Option: C
Explanation:

The image formed by surface of mirror is just like that formed by a mirror.

It is virtual and erect.

Answer-(C)

The phenomena involves in the reflection of radiowaves by ionosphere is similar to

evs magic with mirrors image of an extended object formed by a plane mirror reflection at plane surface introduction to light and mirror

  1. reflection of light by a plane mirror.

  2. total internal reflection of light in air during a mirage.

  3. dispersion of light by water molecules during the formation of a rainbow.

  4. scattering of light by the particles of air.

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Correct Option: B
Explanation:

The ionosphere is the ionized layer of the Earth's atmosphere and its consists of the ions which are formed due to the UV rays coming from the sun. These free electrons result in the reflection of the radio waves and make them reflected back.


This is same as the mirage formation due to the total internal reflection of the rays when the incident angle is greater than the critical angle.

For which of following condition there is no emergent light whatever may be the angle of incidence?

evs magic with mirrors image of an extended object formed by a plane mirror reflection at plane surface introduction to light and mirror

  1. $ A < 2C $

  2. $ A > C $

  3. $ A > 2C $

  4. $ A < C $

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Correct Option: C
Explanation:
For this, we can say that if ${ r } _{ 2 }$ (min) is able to do total internal reflection than definitely all values of ${ r } _{ 2 }$ will perform $TIR$ because min ${ r } _{ 2 }$ has performed that, So, for min ${ r } _{ 2 }$, ${ r } _{ 1 }$ has to be maximum hence $i$ will be maximum,
Applying Snell's law we will get $sin{ r } _{ 1 }=\frac { 1 }{ u } =$ critical angle and for no emergence ${ r } _{ 2 }$ min will be consider us greater than critical angle and hence rest ${ r } _{ 2 }$ will be automatically eligible for $TIR$.
For relation,
${ r } _{ 1 }+{ r } _{ 2 }=A$
We will get ${ r } _{ 1 }+{ r } _{ 2 }=A$
we will get, ${ r } _{ 1 }+{ r } _{ 2 }>2$ (critical angle)
$A>2$ critical angle.