A concave mirror has a radius of curvature of 36cm. At what distance from the mirror should an object be placed to give a real image three times the size of the object?
A
12cm
B
24cm
C
48cm
D
108cm
Verified Correct Answer: B.
Physical Principles & Numerical Solution
F = \(\frac{uv}{u + v}\)
v = 3u
18 = \(\frac{3u \times u}{3u + u}\)
u = 24cm
Source: Myschool Past Questions Archive (Record #28084)