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Physics · PYQ NEET UG 2022
हिन्दीA biconvex lens has radii of curvature, \( 20\text{ cm} \) each. If the refractive index of the material of the lens is \( 1.5 \), the power of the lens is:
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Correct answer · Option A
+5D
Explanation
Using Lens Maker's formula: \( P = \frac{1}{f} = (\mu - 1)(\frac{1}{R_1} - \frac{1}{R_2}) = (1.5 - 1)(\frac{1}{20} - \frac{1}{-20}) = 0.5 \times \frac{2}{20} = \frac{1}{20}\text{ cm}^{-1} = +5\text{ D} \).
