1. An object of size 7.
0 cm is placed at 27 cm in front of a concave
mirror of focal length 18 cm. At what distance from the mirror
should a screen be placed, so that a sharp focused image can be
obtained? Find the size and the nature of the image.
2. . Draw ray diagrams showing the image formation by a convex
mirror when an object is placed (a) at infinity (b) at finite
distance from the mirror
3. How are power and focal length of a lens related? You are
provided with two lenses of focal length 20 cm and 40 cm
respectively. Which lens will you use to obtain more convergent
light?
4. Sudha finds out that the sharp image of the window pane of her
science laboratory is formed at a distance of 15 cm from the
lens. She now tries to focus the building visible to her outside
the window instead of the window pane without disturbing the
lens. In which direction will she move the screen to obtain a
sharp image of the building? What is the approximate focal
length of this lens?
5. A doctor has prescribed a corrective lens of power +1.5 D. Find
the focal length of the lens. Is the prescribed lens diverging or
converging?
6. An object 5.0 cm in length is placed at a distance of 20 cm in
front of a convex mirror of radius of curvature 30 cm. Find the
position of the image, its nature and size.
7. An object is placed at a distance of 10 cm from a convex mirror
of focal length 15 cm. Find the position and nature of the image.
8. An object 5 cm in length is held 25 cm away from a converging
lens of focal length 10 cm. Draw the ray diagram and find the
position, size and the nature of the image formed.
9. One-half of a convex lens is covered with a black paper. Will
this lens produce a complete image of the object? Verify your
answer experimentally. Explain your observations.
10. We wish to obtain an erect image of an object, using a
concave mirror of focal length 15 cm. What should be the range
of distance of the object from the mirror? What is the nature of
the image? Is the image larger or smaller than the object? Draw
a ray diagram to show the image formation in this case.
