home *** CD-ROM | disk | FTP | other *** search
- If the image is within the focal point in the previous
- situation, the rays diverge after they pass through the
- lens. In this case, the image must be formed in front of
- the lens, and the image is virtual. To find the
- magnification and orientation, the light rays are drawn
- as before. The intersection of these rays is found by
- tracing the refracted paths on the real side back to the
- virtual side of the lens, where they will intersect to
- form the image of the man's head. In this case, the third
- ray, traveling through the near focal point, is not used.
- The image in this case is virtual and rightside up.
- If the man is standing at the focal point, the light rays
- reflected from his head emerge from the lens traveling
- parallel to each other. Hence they will not intersect,
- either on the real side or when traced back to the virtual
- side, and the image of the man's head will never be formed.
- Likewise, rays entering a diverging lens never intersect and an
- image is never formed.
-
-