A child stands between two mirrors with his arms out, perpendicular to the mirrors. One plane mirror is 5 m away from his left hand and another plane mirror is 7 m away from his right hand. How far apart are the two images produced by the mirrors if the child has an arm span of 0.5 m?

1.  2 m

2.  12 m

3.  12.5 m

4.  24.5 m

If a ray of light is incident on a plane mirror at an angle 60$°$ from the mirror surface, then deviation produced by the mirror is:

1.  30$°$

2.  60$°$

3.  90$°$

4.  120$°$

The images of clouds and trees in water always less bright than in reality:

1.  because water is forming the image dirty

2.  because there is an optical illusion due to which the image appears to be less bright

3.  because only a portion of the incident light is reflected and quite a large portion goes into water

4.  because the air above the surface of the water contains a lot of moisture

A convex mirror has a focal length = 20 cm. A convergent beam tending to converge to a point 20 cm behind the convex mirror on the principal axis falls on it. The image is formed at:

1.  infinity 

2.  40 cm

3.  20 cm 

4.  10 cm

The largest distance of the image of a real object from a convex mirror of focal length 20 cm can be:

1.   20 cm

2.  infinite

3.  10 cm

4.  depends on the position of the object.

A candle flame of 3 cm is placed at 300 cm from a wall. A concave mirror is kept at distance x from the wall in such a way that the image of the flame on the wall is 9 cm. Then x is:

1.  339 cm 

2.  900 cm

3.  450 cm 

4.  423 cm

A ray of light passes through a plane glass slab of thickness t and refractive index $\mathrm{\mu }$ = 1.5. The angle between the incident ray and emergent ray will be:

1.  0$°$

2.  30$°$

3.  45$°$

4.  60$°$

A fish looking up through the water sees the outside world contained in a circular horizon. lf the refractive index of water is 4/3 and fish is 12 cm below the surface, the radius of the circle in cm is:

1.  $12 \times 3 \times \sqrt{5}$

2.  $4 \times \sqrt{5}$

3.  $12 \times 3 \times \sqrt{7}$

4.  $12 \times 3/\sqrt{7}$

The angle of a prism is 60° and the index of refraction of glass with air is 1.5. If the angle of incidence on the first face is ${\mathrm{I}}_1$ and the angle of emergence at the second face is ${\mathrm{I}}_2$, then the prism produces minimum deviation when:

1.  ${\mathrm{I}}_1 = 0$

2.  ${\mathrm{I}}_1 > {\mathrm{I}}_2$

3.  ${\mathrm{I}}_1 < {\mathrm{I}}_2$

4.  ${\mathrm{I}}_1 = {\mathrm{I}}_2$

A lens of power +2.0 D is placed in contact with another lens of power -1.0D. The combination will behave like:

1.  a converging lens of focal length 100 cm

2.  a diverging lens of focal length 100 cm

3.  a converging lens of focal length 50 cm

4.  a diverging lens of focal length 50 cm