A convex mirror has a radius of curvature of 20 cm. An object is placed in front at such a distance from the mirror that the size of the image is exactly half that of the object. The object distance must be :
Options

Question

A convex mirror has a radius of curvature of 20 cm. An object is placed in front at such a distance from the mirror that the size of the image is exactly half that of the object. The object distance must be :

Options

G1 Physics · Accepted Answer

Derived solution: Step 1: Use the spherical-mirror relation 1/f = 1/v + 1/u with m = - v/u and R = 2f, following the Cartesian sign convention. Step 2: Substitute the values given in the question and apply the geometry/sign convention shown. Step 3: On simplification the result is 10 cm. Therefore the correct option is C.