$A$ beam of light is incident through the holes on side $A$ and emerges out of the holes on the other face of the box as shown in the Figure. Which of the following could be inside the box?

$A$ ray of light is incident obliquely on a glass slab. Draw a ray diagram showing the path of the light ray. Clearly,mark the angle of incidence,angle of refraction,angle of emergence,and lateral displacement of the ray. Give a formula to find the refractive index of the glass slab in terms of the angle of incidence and the angle of refraction.

Which of the following can produce a magnification of $+5$ as well as $-5$?

The image formed by a concave mirror is observed to be virtual,erect and larger than the object. Then the position of the object should be

An object is placed at the following distances from a concave mirror of focal length $15 \, cm$.
$(a)$ $10 \, cm$ $(b)$ $20 \, cm$ $(c)$ $30 \, cm$ $(d)$ $40 \, cm$
Which position of the object will produce:
$(1)$ Virtual image
$(2)$ $A$ diminished real image
$(3)$ An enlarged real image
$(4)$ An image of same size

What is meant by the radius of curvature of a spherical mirror? How is it related to the focal length of the mirror?