The power of a convex lens of focal length 25 cm is ______. - Science and Technology 1

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The power of a convex lens of focal length 25 cm is ______.

Options

  • 4.0 D

  • 0.25 D

  • −4.0 D

  • −0.25 D

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Solution

The power of a convex lens of focal length 25 cm is 4.0 D.

Explanation:

Focal length of the convex lens (f) = 25 cm = 0.25 m

Power of the lens is given by the formula

Power = `1/("f"("in meters"))`

P = `1/0.25`

P = 4 D

For a convex lens, the power of the lens is positive.

Therefore the power of the lens is +4 D.

Concept: Lens
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2021-2022 (March) Set 1

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