It can be summarized as: "Three lines * * * plane, two lines are separated, and two angles are equal". Light is reversible. In the phenomenon of light reflection, the optical paths are equal. When reflecting, reflected light, incident light and normal are all in the same plane. 、
Specular reflection means that parallel light rays are reflected by the interface and emitted in parallel in a certain direction, and the reflected light rays can only be received in a certain direction (the reflecting surface is a smooth plane).
Discovery and detailed introduction of incident angle;
In the first century, Helen, an ancient Greek mathematician studying in Alexandria, found that when light reflected on a mirror, the incident angle was equal to the reflection angle. Why is this? Helen believes that this is because light always travels along the fastest path, and everything that happens in nature follows the fastest and best principle. Helen has been studying the propagation of light for a long time, and plans to sort out her research results and publish a book about mirrors and optics.
Helen is both a mathematician and a physicist, living in Alexandria, Egypt in the 1 century. He left many great achievements in mathematics and science. As early as 1900 years ago, Helen had invented a door that could open automatically, a puppet that could perform by herself, and a weapon that could shoot arrows continuously.
His most famous achievement in astronomy is to determine the distance between Alexandria and Rome according to the position of the moon measured in various regions.