CBSE Class 10 Science 2017 · Paper 31/2/2 · Question 4

The mirror is concave (its hatching, on the right, marks the silvered back). The incident ray passes through the principal focus $F$, so after reflection it travels parallel to the principal axis: draw it from the point of incidence $M$ back to the left, parallel to the axis. Join $M$ to $C$: this radius is the normal at $M$. The angle of incidence $\angle i$ is the angle between the incident ray and the normal $CM$, and the angle of reflection $\angle r$ is the angle between the normal $CM$ and the reflected ray, with $\angle i=\angle r$.