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Where should an object be placed from a ...

Where should an object be placed from a converging lens of focal length 20 cm, so as to obtain a real image of magnification 2?

A

`50 cm`

B

`30 cm`

C

`-50cm`

D

`-30 cm`

Text Solution

Verified by Experts

The correct Answer is:
D
For real image `m = -ve`
`m = -2`
`therefore` As we know `M = f/(mu + F)`
`-2 = f/(u + f) implies -2 = (20)/(u + 20) implies -2 u + (-40) = 20`
`u = - 30 cm`
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