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 :

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Aicharya · Accepted Answer

$\begin{aligned} & m=-3=-\frac{u}{v} \ & u=-x \ & v=-3 x \ & \Rightarrow 2 x=20 \mathrm{~cm}\end{aligned}$ $\begin{aligned} & x=10 \mathrm{~cm} \ & f=\frac{u V}{u+V}=\frac{(-10)(-30)}{(-10)+(-30)}=-7.5 \mathrm{~cm} \ & f=-\frac{R}{2} \ & R=-2 f=15 \mathrm{~cm}\end{aligned}$

A concave mirror produces an image of an object such that the distance between the object and image is 20 cm…

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