Question

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)

Answer 1

8.6 cm

Step-by-step explanation:

Step 1:

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

To find focal length we have,

`(1/u) + (1/v) = (1/f)`

where u = Object distance

v= Image distance

f = Focal length

Step 2:

`(1/f) = (1/20) + (1/15)`

(1/f) = 0.116

f = 1/0.116

f = 8.6 cm