Question

Q6. A convergent beam of light falls on a spherical mirror, the point of convergence being at a distance of 40 cm behind the mirror. After Reflection by the mirror the rays meet at 80 cm in from the mirror. Is the mirror concave or convex ? Calculate its radius of curvature ?

Answer 1

Dear Student,
$$\begin{gathered} Here \\ u=40cm \\ v=-80cm \\ f=? \\ thenbymirrorformula \\ \frac{1}{-80}+\frac{1}{40}=\frac{1}{f} \\ f=\frac{3200}{40}=80cm \\ Soitisconvexmirror \\ andradiusofcurvature=2\times 80=160cm \end{gathered}$$
Regards