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An object placed at a distance of 16 cm ...

An object placed at a distance of 16 cm from a convex lens produces an image of magnification m(m `gt` 1). If the object is moved towards the lens by 8 cm then again an image of magnification m is obtained. The numerical value of the focal length of the lens is

A

12 cm

B

14 cm

C

18 cm

D

20 cm

Text Solution

Verified by Experts

The correct Answer is:
A
m = `(v)/(u) = (f)/(f + u)`
here, m will be equal only when signs are opposite.
Now, `(f)/(f-16) = (-f)/(f-8) rArr f = 12 `cm.
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