A ray of light strikes a flat mirror at 30 degrees to the normal line. At what angle does it leave?

1. The normal line is an imaginary line drawn at right angles to the mirror. 2. The angle of incidence is measured between the arriving ray and that normal line. 3. The angle of reflection is measured between the leaving ray and the same line. 4. For any mirror, the angle of reflection equals the angle of incidence. 5. Here the ray arrives at 30 degrees to the normal. 6. So it leaves at 30 degrees to the normal as well. 7. Answering 60 degrees would come from measuring against the mirror instead of the normal. _Source: Siyavula Natural Sciences Grade 8 (CC BY 4.0), Reflection of light_