A square card of side length 1 mm is being seen through a magnifying lens of focal length 10 cm. The card is placed at a distance of 9 cm from the lens. The appaent area of the card thorugh the lens is

Options

A. `1cm^(2)`
B. `0.81cm^(2)`
C. `0.27cm^(2)`
D. `0.60 cm^(2)`

Answer

A

Explanation

Area = `1mm^(2)`
`(1)/(v) - (1)/(u) = (1)/(f)`
`rArr (1)/(v) = (1)/(f) + (1)/(u) = (1)/(10) - (1)/(9) rArr v = -90 ` cm
m = `(v)/(u) = (-90)/(-9) = 10 `
New area = `m^(2) xx` Initial area
`= (10)^(2) xx 1 = 100 mm^(2) = 1 cm^(2)` .