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A square wire of side 1cm is placed perp...

A square wire of side 1cm is placed perpendicular to the principal axis of a concave mirror of focal length 15cm at a distance of 20 cm. The area enclosed by the image of the wire is

A

`4" cm"^(2)`

B

`6" cm"^(2)`

C

`2"cm"^(2)`

D

`9 cm^(2) `

Text Solution

Verified by Experts

The correct Answer is:
D
`u = - 20 cm, f = -15 cm`.
`(1)/(v) + (1)/(u) = (1)/(f) rArr (1)/(v) = (1)/(-15) - (1)/(-20) = - (1)/(60) rArr = - 60 `cm
Magnification (m) = `(-v)/(u) = - ((-60)/(-20)) = -3`
Areal magnification = `("Linear magnificatio")^(2)`
`therefore (A_(I))/(A_(o)) = 9 rarr (A_(I))/((1)^(2)) = 9 rArr A_(I) = 9 cm^(2).`
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