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A lens is placed between a source of lig...

A lens is placed between a source of light and a wall . It forms images of area `A_(1) "and" A_(2)` on the wall, for its two different positions . The area of the source of light is :

A

`(A_1+A_2)/2`

B

`[1/A_1+1/A_2]^-1`

C

`root_(A_1A_2)`

D

`[(root_A_1+root_A_2)/(2)]^2`

Text Solution

Verified by Experts

The correct Answer is:
A, B, C
`m=sqrt(m_1m_2)` [`because m prop A`]
`thereforeA=sqrt(A_1A_2)`
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