A dentist wants a small mirror that, when 2.90 cm from a tooth, will produce a 1.5✕ upright image

radius-of-curvature

#1

A dentist wants a small mirror that, when 2.90 cm from a tooth, will produce a 1.5✕ upright image. What kind of mirror must be used? What must its radius of curvature be?

Answer:

To get an upright image, convex mirror should be used.
u=2.9 cm
m= 1.5
v=1.5x 2.9 = 4.35 cm
Also
1/f = 1/u + 1/v which gives f = 1.74 cm
radius of curvature = -2f = -2 x 1.74 = - 3.48 cm