A square wire of side `3.0 cm` is placed `25 cm` away from a concave mirror of focal length `10 cm`. What is the area enclosed by the image of the wire ? The centre of the wire is on the axis of the mirror, with its two sides normal to the axis.

Options

A. 4 `cm^(2)`
B. 6 `cm^(2)`
C. 16 `cm^(2)`
D. 36 `cm^(2)`

Answer

A

Explanation

(a) Linear magnification,
`m=I/O=f/(u-f)=10/(25-10)`
`m=10/15=2/3`
A real magnification=`m^(2)=4/9`
Area of image=`4/9xx`area of object
=`4/9xx(3)^(2)=4 cm^(2)`