1. An object 20 cm away from a lens produces a focused image on a film 15 cm away, what is the focal length
of the converging lens? (8.5 cm)

8.6 cm

Explanation:

Step 1:

In this we have to find the focal length of converging lens.

To find focal length we have,

where u = Object distance

           v= Image distance

           f = Focal length

Step 2:

(1/f) =  0.116

f = 1/0.116

f = 8.6 cm

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