Physics - Geometrical Optics Question with Solution | TestHub

PhysicsGeometrical OpticsRefraction at curved surface/LensEasy2 minPYQ_2026

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A convex lens of refractive index $μ$ has two surfaces of equal radius of curvature $R$ . The focal length of convex lens is

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Answer:

Solution:

Using the lens maker's formula:

$\frac{1}{f} = (μ - 1) (\frac{1}{R _{1}} - \frac{1}{R _{2}})$

For a biconvex lens with equal radii of curvature, $R_{1} = + R$ and $R_{2} = - R$ .

Substituting these values into the formula:

$\frac{1}{f} = (μ - 1) (\frac{1}{R} - \frac{1}{- R})$

$\frac{1}{f} = (μ - 1) (\frac{2}{R})$

$f = \frac{R}{2 ( μ - 1 )}$

Answer: $\frac{R}{2 ( μ - 1 )}$

Stream:MHT_CET_MEDICALSubject:PhysicsTopic:Geometrical OpticsSubtopic:Refraction at curved surface/Lens

⏱ 2mℹ️ Source: PYQ_2026

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