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JEE Main202528 Jan 2025Evening ShiftPhysicsRay OpticsActual

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 :

Options

  1. A30 ~cm
  2. B3.75 ~cm
  3. C15 ~cm
  4. D7.5 ~cm

Correct answer

C. 15 ~cm

Step-by-step solution

aligned & m=-3=- u v & u=-x & v=-3 x & 2 x=20 ~cm aligned aligned & x=10 ~cm & f= u V u+V = (-10)(-30) (-10)+(-30) =-7.5 ~cm & f=- R 2 & R=-2 f=15 ~cm aligned

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