Question

A person 1.6 m tall stands 6.4 m from a reflecting globe in a garden.

(a) If the diameter of the globe is 33 cm, where is the image of the person, relative to the surface of the globe? (Enter a negative value if the image forms behind the globe.)

(b) How large is the person's image?

Answer 1

convex mirror so f is negative

R = D/2, f = R/2

f = 33/4 = -8.25 cm

1/f = 1/u + 1/v

1/-8.25 = 1/640 + 1/v

v = -8.145 cm

b) m = -v/u = -(-8.145/640) = 0.01272

hi = m*ho = 0.01272*1.6 = 0.02036 m

hi = 2.036 cm