A dentist obtains a linear magnification of 4 of a hole in a tooth by placing a concave mirror at a distance, of 2.0cm from the tooth. The radius of Curvature of the mirror is
A
5.3cm
B
3.2cm
C
2.7cm
D
1.6cm
Verified Correct Answer: B.
Physical Principles & Numerical Solution
v = 4u, if u = 2cm, v = 8cm
F = \(\frac{uv}{u + v}\)
= \(\frac{2 \times 8}{2 + 8}\)
= 1.6cm
r = 2F
= 2 x 1.6
= 3.2cm
Source: Myschool Past Questions Archive (Record #28529)