Question

find the power of concave lens of focal length 2.5 m

Answer 1

Hey...As we know the focal length of concave lens is negative, and the power is inversely proportional to the focal length. hence,

P=1/f
=1/2.5
=10/25
=2/5
=0.4D

Answer 2

The power of the concave lens is (-40 D).

Explanation:

Given that,

Focal length of the concave lens, f = -2.5 m (negative for concave lens)

We need to find the power of the concave lens. We know that the relation between the focal length and the power of a lens is given by :

$P=\dfrac{1}{f}\\\\P=\dfrac{100}{(-2.5)}\ D\\\\P=-40\ D$

So, the power of the concave lens is (-40 D).

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Power of a lens

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