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Ray Optics

JEE Main level, single correct, medium

139 of 295

Question 139 of 295

The radii of curvature for a thin convex lens are 10 cm and 15 cm respectively. The focal length of the lens is 12 cm. The refractive index of the lens material is

Show answer and solution

Answer: (C) 1.5

\begin{aligned} & \frac{1}{\mathrm{f}}=(\mu-1)\left(\frac{1}{\mathrm{R}_1}-\frac{1}{\mathrm{R}_2}\right) \\ & \frac{1}{12}=(\mu-1)\left(\frac{1}{10}-\frac{1}{-15}\right) \\ & \frac{1}{12}=(\mu-1)\left(\frac{3+2}{30}\right) \\ & \mu=\frac{3}{2}\end{aligned}

JEE Main question paper PDF

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JEE Main 2025 Apr 2 Shift 1 question paper

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