Answer to Question #22305 in Mechanics | Relativity for Shaan

Question

A dentist uses a small mirror of radius 38 mm to locate a cavity in a patient's tooth. If the mirror is concave and is held 11 mm from the tooth, what is the magnification of the image?

Answer 1

R = 38 mm,
object = 11 mm
The focus is halfway of the radius, so f = R/2 = 19 mm.

The mirror equation is 1/image + 1/object = 1/f, so the image is at
image = 1/(1/f - 1/object) = 1/(1/19 - 1/11) mm = -26.13 mm.

The magnification is image/object = 26.13 / 11 = 2.37

Answer: about 2.37