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A 5.0 diopter lens forms a virtual image...

A 5.0 diopter lens forms a virtual image which is 4 times the object placed perpendicularly on the principal axis of the lens. Find the distance of the object from the lens.

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The correct Answer is:
A, C
`h_i=4h_0, h_i/h_0=4`
`h_i/h_0=v/(-u)rarr (-v)/u=4, v-4u`
`1/v-1/u=1/f`
`1//f=P=5, f=1/5m=20cm`
`1/(-4u)+1/u=1/20`
`3/(4u)=1/20rarr u=60/415cm`
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