Question

the focal length of a convex lens is 40cm calculate the power of lens​

Answer 1

Explanation:

Given :

• Focal length 40 cm

To Find :

• alculate the power of lens

Solution :

Concept :

• The S.I unit of Power of lens (P) is dioptres (D) and Focal length is to be measured in metres (m) according to the formula you’ve

Given i.e. P = 1/f

If you choose f to be in centimetres (cm), then you must choose the formula, P = 100/f.

• P = 1 / F (in m)

Substitute all values :

➦ P = 1 / 0.4 m

➦ P = + 2 . 5D

more to know :

Power :

• Power is defined as the time rate at which work is done or energy is transferred by it.

Focal length :

• Focal length is the distance between the centre of a lens or curved mirror and its focus.

Answer 2

Explanation:

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