According to the principle of plane mirror imaging: obey the law of light reflection.

The imaging law of plane mirror: the object becomes a virtual image in the plane mirror, the size of the image and the object is the same, the distance between the image and the object and the mirror surface is equal, and their connecting lines are perpendicular to the mirror surface. Images and things are upside down. So when you set the clock to 9 o'clock, look in the mirror. The clock in the mirror shows 3 o'clock.

Law of light reflection: reflected light is in the same plane as incident light and normal line; Reflected light and incident light are separated on both sides of the normal; The reflection angle is equal to the incident angle. It can be summarized as: "Three lines are in a plane, two lines are separated, two angles are equal, and the optical path is reversible".

Extended data:

Features:

1. The object becomes an upright and equal virtual image in the plane mirror.

2. The line between the image and the object is perpendicular to the mirror.

3. The distance from the image to the plane mirror is equal to the distance from the object to the plane mirror.

4. Images and objects are symmetrical about a plane mirror.

5. The virtual image cannot be accepted by the light curtain.

6. The images are equal in size, consistent from top to bottom and opposite from left to right.

Reference: Baidu Encyclopedia-Imaging Principle of Plane Mirror