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Lens Formula

A small objec...

Question

A small object is so placed in front of a convex lens of 5cm focal length that a virtual image is formed at a distance of 25 cm . Find the magnification

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Solution

I/f=1/v-1/u
1/5=1/-25-1/u
-1/25-1/5=1/u
(-1-5)/25=1/u
-6/25=1/u. U=-25/6
Magnification=v/u
-25/(-25/6)=6

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