Question

And object is 20 cm from the lens. The image from 6.66667 cm from the length. What is the focal length of the lens? Use the thin lens equation

Answer 1

5

Step-by-step explanation:

The object distance Is 20 I'm

The image distance is 6.666

Therefore the focal length can be calculated as follows

1/f = 1/20 + 1/6.66

= 6.66+20/133.2

= 26.66/133.2

1/f= 26.66/133.2

f = 133.2/26.66

= 4.99

= 5

Hence the focal length is 5