You are provided with two lenses of focal lengths 10cm and 20cm. Which of the two lenses would you suggest to obtain greater convergence on refracted light? Justify your choice.

How is the reflection of light ray from a plane mirror different from the refraction of light ray as it enters a block of glass?

A convex lens of power 5D and a concave lens of power 7.5D are placed in contact with each other. What is the:

1. Power of this combination of lenses?
2. Focal length of this combination of lenses?

The following table gives the refractive indices of a few media,

	1	2	3	4	5
Medium:	Water	Crown glass	Rock salt	Ruby	Diamond
Refractive index:	1.33	1.52	1.54	1.71	2.42

Use this table to give an example of:

1. A medium pair so that light speeds up when it goes from one of these medium to another.
2. A medium pair so that light slows down when it goes from one of these medium to another.

A concave mirror produces three times magnified real image of an object placed at 10 cm in front of it. Where is the image located?

Describe with a suitable diagram, how a convex mirror diverges a parallel beam of light rays. Mark clearly the pole, focus and centre of curvature of convex mirror in this diagram.

Draw ray diagrams showing the image formation by a concave mirror when an object is placed:
Between pole and focus of the mirror.

Draw a ray diagram to show the path of the reflected ray corresponding to an incident ray which is directed towards the principal focus of a convex. mirror. Mark on it the angle of incidence and the angle of reflection.

List two properties of the images formed by convex mirrors. Draw ray diagram in support of your answer.

Name the two types of spherical mirrors. What type of mirror is represented by the:

1. Back side of a shining steel spoon?
2. Front side of a shining steel spoon?