An object is placed in front of a converging lens of a focal length 20cm. The image is virtual and has a magnification of 2. What is the distance of the object from the lens?
A
5cm
B
10cm
C
30cm
D
40cm
Verified Correct Answer: B.
Physical Principles & Numerical Solution
V = -2u
F = \(\frac{uv}{u + v}\)
20 = \(\frac{uv - 2u}{u - 2u}\)
u = 10cm
Source: Myschool Past Questions Archive (Record #27926)