Question:medium

What is the focal length of a lens if its power is \( +2 \, \text{D} \)?

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Remember: The power of a lens is the reciprocal of its focal length. The unit of power is diopter (D), and the focal length is in meters.
Updated On: Nov 26, 2025
  • 0.5 m
  • 1.0 m
  • 2.0 m
  • 0.2 m
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The Correct Option is A

Solution and Explanation

Step 1: Employ the lens power formula The lens power \( P \) is calculated using its focal length \( f \) via the equation:\[P = \frac{1}{f}\]Definitions:- \( P \) denotes lens power (diopters),- \( f \) signifies focal length (meters).Step 2: Determine \( f \) With a lens power of \( P = +2 \, \text{D} \), substitute this value into the formula:\[2 = \frac{1}{f}\]Solving for \( f \):\[f = \frac{1}{2} = 0.5 \, \text{m}\]Answer: Consequently, the lens exhibits a focal length of 0.5 m. This corresponds to option (1).
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