The driving mirror of a car has a radius of curvature of 1m. A vehicle behind the car is 4m from the mirror. Find the image distance behind the mirror.
A
8/7
B
4/9
C
9/2
D
4/7
Verified Correct Answer: B.
Physical Principles & Numerical Solution
Thus if r = 1m
f = 1/2 = 0.5m
∴ if U = - 4m (object behind mirror)
f = 0.5m
\(\frac{1}{u}\) + \(\frac{1}{v}\) = \(\frac{1}{f}\)
-\(\frac{1}{4}\) + \(\frac{1}{v}\) = \(\frac{1}{0.5}\)
\(\frac{1}{v}\) = 2 + \(\frac{1}{4}\)
\(\frac{1}{v}\) = \(\frac{1+ 8}{4}\)
\(\frac{1}{v}\) = \(\frac{9}{4}\)
v = \(\frac{4}{9}\)
Source: Myschool Past Questions Archive (Record #2005)