Question

What is meant by the power of a lens ? What is its S.I. unit ? Name the type of lens whose power is positive.
The image of an object formed by a lens is real, inverted and of the same size as the object. If the image is at a distance of 40 cm from the lens, what is the nature and power of the lens ? Draw ray diagram to justify your answer.

Answer 1

Answer:

Power of a lens is defined as its ability to converge or diverge light rays.

SI unit: Dioptre, denoted by D

Nature of lens: Convex

Power of lens: 0.05 D

Refer to the attachment for the diagram.

Explanation:

Given:

• m = -1
• u -40 cm
• v = + 40

To find:

• focal length, f = ?
• power, P = ?

Solution:

Since, numerically, v = u = 40 cm,

The object and the image both are at 2F.

So, F = 40/2

F = + 20 cm

Power of lens, P = 1/f = 1/20 = 5/100 = + 0.05 D

Answer 2

Answer:

hope this helps you

mark me as brainlist