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.

Draw a diagram to represent a convex mirror. On this diagram mark principal axis, principal focus F and the centre of curvature C if the focal length of convex mirror is 3cm.

What is the position of the image when an object is placed at a distance of 20cm from a concave mirror of focal length 20cm?

A 4 cm tall object is placed on the principal axis of a convex lens. The distance of the object from the optical centre of the lens is 12cm and its sharp image is formed at a distance of 24cm from it on a screen on the other side of the lens. If the object is now moved a little away from the lens, in which way (towards the lens or away from the lens) will he have to move the screen to get a sharp image of the object on it again? How will the magnification of the image be affected?

What is meant by:

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

1. How can you bend light away from the normal?
2. How must light travel out of a substance if it is not going to be refracted?

Find the focal length of a lens of power – 2.0 D. What type of lens is this?

Draw ray diagrams showing the image formation by a concave lens when an object is placed:Between focus and twice the focal length of the lens.

Why does a beam of light when it enters glass at an angle? Why does it not bend if it inters the glass at right angles?

A lens is cut into two equal halves: Along the principal axis.
What will be the focallength of each half?