Question
It is desired to obtain an erect image of an object, using a concave mirror of focal length 20 cm.
(i) What should be the range of distance of the object from the mirror?
(ii) Will the image be bigger or smaller than the object.
(iii) Draw a ray diagram to show the image formation in this case.
Solution
We are given a concave mirror for which, an erect image has to be obtained.
Focal length, f = 20 cm
(i) The object should be placed, at a distance between 0 to 20 cm i.e., between the pole and focus of the mirror.
(ii) The image formed, will be bigger than the object.
(iii) The image is formed behind the mirror and is highly enlarged; is virtual and erect.
Fig. Image formed by a concave mirror with the object between F and P
Focal length, f = 20 cm
(i) The object should be placed, at a distance between 0 to 20 cm i.e., between the pole and focus of the mirror.
(ii) The image formed, will be bigger than the object.
(iii) The image is formed behind the mirror and is highly enlarged; is virtual and erect.
Fig. Image formed by a concave mirror with the object between F and P
