Question

A student has focused the image of a candle flame on a white screen using a concave mirror. The situation is as given below:
Length of the flame = 1.5 cm
Focal length of the mirror = 12 cm
Distance of flame from the mirror = 18 cm

If the flame is perpendicular to the principal axis of the mirror, then calculate the following:
(a) Distance of the image from the mirror
(b) Length of the image
If the distance between the mirror and the flame is reduced to 10 cm, then what would be observed on the screen? Draw ray diagram to justify your answer for this situation.

Answer 1

Given: height of object, h= +1.5cm; focal length,f = -12cm; object distance, z = -18 cm; image distance, v = ?; height of image, h' = ?

lf u =- 10 cm, no distinct image would be formed on the screen. In this case the image formed will be virtual.