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
Correct Answer: Option B
Explanation
V = -2u
F = (frac{uv}{u + v})
20 = (frac{uv – 2u}{u – 2u})
u = 10cm