Question

Comment on the size, position of the image formed by a concave mirror of focal length
18 cm when an object is placed:
(i) at 22 cm
(ii) 14 cm
(iii)40 cm.
in front of mirror without calculations.

Answer 1

The size and position of the image formed by a concave mirror when an object is placed at three different lengths along the principal axis can be given without calculations and are dependent on their relative position with the focus of the given mirror.

For an object at (i) 22 cm distance from optical centre O, the image is enlarged and located beyond the centre of curvature.

For an object at (ii) 14 cm distance from the optical centre, the image is enlarged and located behind the mirror.

For an object at (iii) 40 cm distance from the optical centre, the image is diminished and located between the centre of curvature and focus.