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JAMB Physics 2024 Paper

Question : 76

Total: 125

The power of a convex lens of focal length 20cm is

Solution:

Concept:

Power of a lens

P

is the reciprocal of the focal length

f

measured in metres:

P = \frac{1}{f}

Explanation:

Convert focal length to metres:

f = 20\ \text{cm} = 0.20\ \text{m}

Substitute into the formula:

P = \frac{1}{0.20} = 5.00\ \text{D}

A convex lens has positive power, so the power is

+5.00

dioptres.

Answer:

5.00\ \text{D}

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