The image of an object is located 6cm behind a convex mirror. If its magnification is 0.6, calculate the focal length of the mirror
A
3.75cm
B
6.60cm
C
10.00cm
D
-15.00cm
Verified Correct Answer: D.
Physical Principles & Numerical Solution
V = -6cm
M = 0.6cm
Recall m = \(\frac{V}{U}\)
U = \(\frac{V}{M}\)
U = \(\frac{6}{0.6}\)
U = 10
\(\frac{1}{U}\) + \(\frac{1}{V}\) = \(\frac{1}{F}\)
\(\frac{1}{10}\) + \(\frac{1}{-6}\) = \(\frac{1}{F}\)
\(\frac{-4}{60}\) = \(\frac{1}{F}\)
F = \(\frac{60}{-4}\)
= -15cm
Source: WAEC / JAMB / NECO Classroom Archive (Record #25489)