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QJEEM25Ph4b01: JEE Main 2025 Physics - Class 12 JEEM25Ph4b01 Solution: A concave mirror produces an image of an object such that the…

A concave mirror produces an image of an object such that the distance between the object and image is 20 cm. If the magnification of the image is –3, then the magnitude of the radius of curvature of the mirror is :

Multiple Choice Options

  • A 3.75 cm
  • B 15 cm
  • C 7.5 cm
  • D 30 cm

Step-by-Step Verified Solution

JEE Main 2025 (Online) 28th January Evening Shift Physics - Geometrical Optics Question 14 English Explanation

amp;m=−3=−vu and v−u=20 cmamp;f=vuv+u=(−30)(−10)−30−10amp;∴R=+15\begin{aligned}& \mathrm{m}=-3=-\frac{\mathrm{v}}{\mathrm{u}} \text { and } \mathrm{v}-\mathrm{u}=20 \mathrm{~cm} \\& \mathrm{f}=\frac{\mathrm{vu}}{\mathrm{v}+\mathrm{u}}=\frac{(-30)(-10)}{-30-10} \\& \therefore \mathrm{R}=+15\end{aligned}

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