Question

Draw a labelled ray diagram to locate the image of an object fromed by a convex lens of focal length 20 cm when the object is placed 30 cm away from the lens.

Answer 1

Here, `v=?, f=20 cm, u= -30 cm`,
From `(1)/(v)-1/u=(1)/(f)`,
`(1)/(v)=(1)/(f)+1/u=(1)/(20)-(1)/(30)=(3-2)/(60)=(1)/(60)`
`v=60 cm`
The labelled ray diagram is