A dentist wants a small mirror that, when 2.20 cm from a tooth, will produce a 4.5 X upright image. What kind?

of mirror must be used and what must its radius of curvature be?

concave mirror, virtual upright image. v/u =4.5 or v=4.5u=9.9cm
i/f =1/u +1/v =1/2.20 -1/9.9 =0.45 -0.10 =0.35
f=
f=2.86 cmanswer
a concave mirror of focal length 2.86 cm. answer

Concave mirror for an upright virtual image
M=-di/do
4.5=-di/(2.2 cm)
di=-9.9 cm
1/f=1/do + 1/di
1/f=1/(2.2 cm) + 1/(-9.9 cm)
f=2.826 cm
r=2f
r=2 x (2.826 cm)
r=5.657 cm

I hope this helps you “see” the lesson in the problem

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