Question

(a) A dentist uses a mirror in front of a decayed tooth at a distance of 4cm from the tooth to get a 4 times magnified image . Use mirror formula to find the focal length and nature of mirror used . Whar is nature of image? (b) If a mirror produces a magnification of 1.3 When an object is placed at a distance of 20 cm from the mirror , find the position of image .

Answer 1

m = -v/u = 4

u = -4 cm

v = 16 cm thus, the image is virtual and erect

1/f = 1/v + 1/u

f = -3/16 cm thus the mirror is convex

if m = 1.3 and u = -20cm

v = 1.04 m or 104 cm

Hope it helps :-)