An object is placed in front of a converging lens of a focal length 20cm....

JAMB 1994

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

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Correct Answer: Option B

Explanation

V = -2u

F = \(\frac{uv}{u + v}\)

20 = \(\frac{uv - 2u}{u - 2u}\)

u = 10cm

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An object is placed in front of a converging lens of a focal length 20cm....

Correct Answer: Option B

Explanation

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