Question

An object is placed on the axis of a convex lens.Its image is formed 80cm from the object.The magnification is 3 .The focal length of the lens is

Answer 1

Answer:

1.5

Explanation:

its is a convex lens

Answer 2

Answer:

F= 15cm

Explanation:

Given that |u|+v = 80cm._____(1)

Also,3=v/u

V=3U subsituting in (1)

We get, u=20cm and v= 60cm

Using lens formula,

1/f=1/v-1/u

We get,

F=15cm