One comes from the object and travels parallel to the principal axis and therefore appears to originate from the focal point F after reflection from the mirror.
The second ray heads toward F, emerging parallel to the principal axis after reflection.
The third ray travels toward the center of curvature C; as a result it strikes the mirror perpendicularly and reflects back on itself.
The green lines are the virtual rays as they appear to an observer.
The gray lines are light rays.
The red arrow is the object and the gray arrow is the resulting virtual image. You can move the object by either draging it or by clicking to the location of your choice.
Last modified: June 20, 1997
