An object of height 6cm is placed at a distance of 30cm in front of a mirror of radius of curvature 60cm. Calculate
position and size of image if the mirror is-(i) concave mirror and (ii) convex mirror. Give ray diagram for each case too.
Answers
Answer:
= - 20 cm
ho = 5 cm
R = + 30 cm ... (convex mirror)
begin mathsize 12px style straight f equals straight R over 2 equals 30 over 2 equals plus 15 space cm space left parenthesis convex space mirror right parenthesis
From space the space mirror space formula comma space we space get
1 over straight f equals 1 over straight u plus 1 over straight v
rightwards arrow 1 over straight v equals 1 over straight f minus 1 over straight u
rightwards double arrow 1 over straight v equals 1 over 15 minus fraction numerator 1 over denominator negative 20 end fraction
rightwards double arrow straight v equals 8.57 space cm end style
The image is formed at a distance of 8.57 cm behind the convex mirror. Thus, it is virtual and erect.
m space equals space minus space v over u space space
m space equals negative space space fraction numerator 8.75 over denominator negative space 20 end fraction space equals space 0.4 space
A l s o comma
m space equals space h subscript i over h subscript o space
0.4 space equals h subscript i over 5 space
h subscript i space end subscript space equals space 0.4 space cross times space 5 space equals space 2 space c m
Thus, the height of an image is 2 cm.
Thus, we can say that tha image is diminished