Question

An erect image 2.0 cm high is formed 12 cm form a lens, the object be ing 0.5 cm high .Find the focal length of the lens.

Answer 1

I = 2 cm
V = 12 cm
O = 0.5
U = ? F=?
Now
I/O =V/U
so , U = 3
1/f = 1/U + 1/V
Hence ,
F = 2.4 cm