Question

The image of an object placed at 30 cm in front of a lens is obtained on a screen at a

distance of 60 cm from it. Find the focal length of the lens. Write about nature and size

of image​

Answer 1

Answer:

Magnification is 3 times and image distance v=80cm

Magnification =

u

v

Or,3=

u

80cm

Or, u=

3

80cm

since,object distance is taken as negative; as per sign convention so,

or, u=−

3

80cm

Nature of image: since image is formed on the other side of lens hence it is a real image and inverted image.

Nature of Lens: Enlarged image is formed by convex lens and not by concave lens, so it is a convex lens.