Question

the image formed by a convex lens is equal distance from the lens is 20 CM so what is the power of the convex lens​

Answer 1

Answer:

Concave and convex lenses, each have the same focal length 20cm and they are put in contact to form a combination lens. This combination lens is used to view an object of 5cm length, kept at a distance 20cm from the lens combination. As compared to the object the image will be

Answer 2

Given,

distance of image from the lens = 20 cm

To find,

power of convex lens

Solution,

The power of a lens is the reciprocal of its focal length.

Since the image is formed at equal distance length as that of the object. The object is placed at center of curvature.

Centre of curvature = 2 × focal length

20 = 2f

10 cm = f

Power of lens = 1/f

Power of lens = 1/20

Power = 0.05

Hence, the power of the convex lens is 0.05 diopter.