Tag: magic with mirrors

Questions Related to magic with mirrors

On reflection from a rigid body, the wave undergoes a phase change of

  1. $90^{\circ}$

  2. $180^{\circ}$

  3. $210^{\circ}$

  4. $120^{\circ}$


Correct Option: B

When you see your reflection in the inner surface of the spoon, choose the correct option regarding the image formed

  1. The image formed will be erect only, it can not be inverted

  2. The image formed will be inverted only, it can not be erect

  3. The image formed can be both erect or inverted depending upon distance of your face and the spoon

  4. The image formed will be real


Correct Option: C
Explanation:

Since inner surface of spoon act as concave mirror i.e. erect or diminished or virtual or real with varyaccording to position of object.

A small object is placed 10cm in front of a plane mirror. If you stand behind the object 30 cm from the object and look at its image, the distance focused for your eye will be :

  1. $60 cm$

  2. $20cm$

  3. $40 cm$

  4. $80 cm$


Correct Option: C

When a ray of light is incident normally on a plane mirror then the angle of reflection will be?

  1. ${0}^{o}$

  2. ${90}^{o}$

  3. ${180}^{o}$

  4. $-{90}^{o}$


Correct Option: A
Explanation:

As angle of incidence and angle of reflection is always equal hence angle of reflection should be $0°$ as normal to the plane incidence means $0°$ is the angle of incidence from normal.

A monochromatic ray of light in glass strikes the glass air interference normally. which of the following correct?

  1. The ray is totally reflected into glass

  2. The ray passes into air such that the
    refracted ray bends away from the normal

  3. The ray passes into air undeviated and with an increase in its speed.

  4. The ray passes into air with an increase in its frequency.


Correct Option: A

Two plane mirrors A and B are aligned parallel to each other, as shown in figure. A light ray is incident at an angle $30$ at a point just inside one end of A. The plane of incidence coincides with the plane of the figure.The maximum number of times the ray undergoes reflections ( including the first one) before it emerges out is:

  1. $28$

  2. $30$

  3. $32$

  4. $34$


Correct Option: B

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