When the light hits the interface
Reflection angle be equal to Angle of incidence ; (Two corners are equal) Incident light, Reflected light And normal In the same plane (three lines Coplanar ） Incident light, Reflected light On both sides of the normal, and symmetrical about the normal. (Two wires on the opposite side) Attachment: Law of refraction ：sin θ one /sin θ two = v one / v two = n two / n one Incident light, Refraction ray In the same plane as the normal (three lines coplanar) Incident light, Refraction ray On both sides of the normal, but asymmetrical. (Two wires on the opposite side) When the light hits the interface,
Refraction angle Greater than the angle of incidence (from liquid and glass to air) (relationship between two angles) Refraction angle Less than the angle of incidence (from air to liquid, glass) (relationship between two angles) Refraction angle Equal to the incident angle equal to 0 ° (vertically projecting from one substance to another) (relationship between two angles) 
