Question

find the image distance when focal length is 40 and object distance is 12​

Answer 1

Answer:

120/13 cm

Explanation:

Gaussian form of lens equation:

1/o + 1/i = 1/f

Where i is image distance, o is object distance and f is focal length in cm.

Note: In the Gaussian form, object distance is negative.

-1/12 + 1/i = 1/40

1/i = 1/40 + 1/12

1/i = 13/120

i = 120/13 cm

Hope this answer helped you.