Question

if an object is placed at distance of 40cm from a convex lens of focal length 15cm. where and at what distance the image formed? will the image be virtual or real. .

Answer 1

Heya

We can use the lens formulae here

Object distance = 40cm

Focal length = 15cm

1/f = 1/v - 1/u

Using sign convention

1/15 = 1/v - 1/(-40)

1/15 = 1/v + 1/40

1/15 - 1/40 = 1/v

(8-3)/120 = 1/v

5/120 = 1/v

1/24 = 1/v

v=24cm

The image will be formed at 24cm. The image will be a real one.