Height of object, h = 4.5 cm, u = – 12 cm.
f = 15 cm, v = ? m = ?
1/v = 1/f - 1/u = 1/15 - 1/(-12) = 1/15 + 1/12
⇒ 1/v = (4 + 5)/60 = 9/60
∴ v = 60/9 = 6.7 cm.
m = h'/h = c/u
∴ h' = v/u x h = -(6.7/-12) x 4.5 = 2.5 cm.
The image is virtual and erect. As the needle is moved farther from the mirror, the image moves away from the mirror