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Questions
If focal length of a convex lens is 20 cm at what is the power of the lens?
The focal length of a convex lens is 20 cm. What is its power?
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Solution
Given: Focal length (f) = 20 cm = 0.2 m
To find: Power of the lens (P)
Formula: P = `1/("f"("m"))`
Calculation: From formula,
P = `1/0.2`
= 5 D
∴ The power of the convex lens is 5 D.
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