Question

Draw ray diagrams to determine the nature and position of the image formed by a concave mirror when the object is between the principal focus and the pole of the mirror.

Answer 1

Object in between the Focus and Pole of the Mirror

1. Fig. shows the object PQ between the focus F and the pole O of the concave mirror. Ray 1 is parallel to the principal axis so that ray 1' passes through F.
2. The ray 2 appears to pass through the centre of curvature C and, therefore, retraces its path as ray 2'.
3. The two reflected rays 1' and 2' form a divergent beam, i.e., do not meet at any point.
4. However, when produced backward the two rays appear to meet at point Q'. Clearly Q' is a virtual image of the point Q of the object and P'Q' is the image of PQ.
5. Here, the image formed is virtual, erect, enlarged, and behind the mirror.