Question

(a) Draw ray-diagrams to show the formation of images when the object is places in front of a concave mirror (converging mirror):
(i) between its pole and focus
(ii) between its centre of curvature and focus
Describe the nature, size and position of the image formed in each case.
(b) State one use of concave mirror bases on the formation of image as in case (i) above.

Answer 1

(i) When an object is placed between the pole and the focus of a concave mirror, the image formed is virtual, erect, magnified and behind the mirror. This is illustrated as follows:

Here, the image A'B' of the object AB, placed between the pole and the focus of a concave mirror, is virtual and erect.

(ii) When an object is placed between the centre of curvature and the focus of a concave mirror, the image formed is real, inverted, and enlarged. This is illustrated as follows:

Here, the image A'B' of the object AB, placed between the centre of curvature and the focus of a concave mirror, is real and inverted.

(iii) The concave mirror can be used in the following, on the bases of image formation as demonstrated in case (i):

1. As a shaving mirror
2. As a make-up mirror
3. As a dentist's mirror