Question

"An object is placed 10 cm in front of a converging lens with a 4

cm focal length.
a) Draw 3 special rays and the resulting image.

Answer 1

(a) The three special ray diagram shown in the image attached converges to form the image formed as an inverted image.

How to the draw the special ray diagrams?

(a) The ray diagram will consists of ray that will pass through the focal point, principal axis and center of curvature.

The position of the image formed is calculated as follows;

1/f = 1/u + 1/v

where;

• u is the object distance
• v is the image distance
• f is the focal length

1/4 = 1/10 + 1/v

1/v = 1/4 - 1/10

1/v = (5 - 2)/20

1/v = 3/20

v = 20 / 3

v = 6.67 cm

So the position of the image is 6.67 cm.