Question

a dentist's places is mirror of focal length 4 cm at a distance of 2 cm from the tooth of his patient find the position of image of the tooth (4cm behind the mirror.)​

Answer 1

Explanation:

f=-4,u=-2

1/f=1/u+1/v

1/v=1/f-1/u

1/v=(1/-4)-(1/-2)

1/v=1/8

v=8

magnification=-v/u

=-8/-2

=4cm

Hence,the image is 4 times the size of the given object.