Draw a ray diagram to show the formation of a virtual magnified image of an object by a convex lens. In your diagram, the position of object and image with respect to the principal focus should be shown clearly.

What is meant by:

1. Principal focus of a convex mirror.
2. Focal length of a convex mirror?

A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens.

If a ray of light is incident on a plane mirror such that it makes an angle of 30with the mirror, then will be the angle of reflection?

What kind of lens can form:

1. An inverted magnified image?
2. An erect magnified image?
3. An inverted diminished image?
4. An erect diminished image?

At what distance from a converging lens of focal length 12cm must an object be placed in order that an image of magnification 1 will be produced?

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?

With the help of a labelled ray diagram, describe how a converging mirror can be used to give an enlarged upright image of an object.

It is desired to obtain an erect image of an object, using concave mirror of focal length of 12cm.
Where will the image of this object be, if it is placed 24cm in front of the mirror? Draw ray diagram for this situation also to justify your answer.
Show the positions of pole, principal focus and the centre of curvature in the above ray diagrams.

How could you find the focal length of a convex lens rapidly but approximately?