Tag: reflection at plane surface

Questions Related to reflection at plane surface

Two plane mirrors are inclined to each  other such that  a ray of light incident on the first  mirror $\left( { M } _{ 1 } \right) $ and parallel to the second mirror $\left( { M } _{ 2 } \right) $  is finally reflected from the second mirror $\left( { M } _{ 1 } \right) $ parallel to the two mirroes will  be : 

  1. ${ 90 }^{ 0 }$

  2. ${ 75 }^{ 0 }$

  3. ${ 45 }^{ 0 }$

  4. ${ 60 }^{ 0 }$


Correct Option: D

Two plane mirror are inclined to each other such that a ray of light incident on the first mirror $\left( { M } _{ 1 } \right) $ and parallel to the second mirror $\left( { M } _{ 2 } \right) $ is finally reflected form th second mirror $\left( { M } _{ 2 } \right) $ parallel to the first mirror $\left( { M } _{ 1 } \right) $ the angle between the two mirrors will be :

  1. ${ 60 }^{ 0 }$

  2. $75^{ 0 }$

  3. $90^{ 0 }$

  4. $45^{ 0 }$


Correct Option: A

a particle is moving in front of a plane mirror as shown in figure. Velocity of image with respect to object is -

  1. $V sin \theta$

  2. $V cos \theta$

  3. $2V sin \theta$

  4. $2 V cos \theta$


Correct Option: B

If the mirror is displaced by a distance 4 cm, towards the object, the image is displaced by 

  1. 12 cm

  2. 4 cm

  3. 6 cm

  4. 8 cm


Correct Option: D

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 $\hat i + \hat j$

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

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

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

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


Correct Option: C

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

  1. The image formed is real

  2. The image formed is inverted

  3. The image formed is erect

  4. None of the above


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

  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.


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?

  1. $ A < 2C $

  2. $ A > C $

  3. $ A > 2C $

  4. $ A < C $


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.

Fill in the blank:

A boy blinks his right eye. Mirror image of the boy blinks its ______ eye.

  1. both

  2. right

  3. none

  4. left


Correct Option: D
Explanation:

Due to lateral inversion by mirror, right appears on left and left appears on right.

The image formed by a plane mirror is always ....... inverted.

  1. laterally

  2. virtually

  3. really

  4. none


Correct Option: A
Explanation:

The image formed by a plane mirror is always Laterally inverted.