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An object placed 10 cm in front of a len...

An object placed `10 cm` in front of a lens has an image `20 cm` behind the lens. What is the power of the lens`(` in diopters `)` ?

A

`1.5`

B

`3.0`

C

`-15.0`

D

`+15.0`

Text Solution

Verified by Experts

The correct Answer is:
D
`u=-10cm, v=20cm`
`(1)/(f)=(1)/(v)-(1)/(u)=-(1)/(20)-((-1)/(10))=(3)/(20)impliesf=(20)/(3)cm`
Now, `F=(100)/(f)=(100)/(20//3)=+15D`
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