Question

The angle between an incident ray and the normal to the surface of the mirror is ${40}^o$.

1. What is the angle of incidence?
2. What is the angle of reflection?

Answer 1

1. The angle of incidence -

• The angle that the incident ray makes with the normal at the point of the incident is known as the angle of incidence$\angle i$.
• According to the question, the angle between an incident ray and the normal to the surface of the mirror is ${40}^o$, therefore$\angle i={40}^o$.

b. The angle of reflection -

• The angle that the reflected ray makes with the normal at the point of the incident is known as the angle of reflection$\angle r$.
• According to the law of reflection, the angle of incidence is equal to the angle of reflection, i.e. $\angle r=\angle i$
• Therefore,$\angle r={40}^o$.

Final answer - a. The angle of incidence is ${40}^o$.

b. The angle of reflection is ${40}^o$.