Question

A 4.0 cm object is 6.0 cm from a convex mirror that has a focal length of 8.0 cm. What is the height of the image produced by the mirror?

Answer 1

ho = object height = 4 cm

p = object distance = 6 cm

f = focal length = -8 cm (f is negative for a convex mirror)

q = image distance

M = magnification = -q/p

hi = image height = M*ho

1/p + 1/q = 1/f

1/6 + 1/q = -1/8 ⇒ q = -3.429 cm

M = -q/p = -(-3.429)/6 = 0.5715

hi = M*ho = (0.5715)(4 cm) = 2.286 cm