Photographs of the ground are taken from an aircraft at an altitude of 2000 m by a camera with a lens of focal length 0.50m. The size of the film in the camera is `0.18m xx 0.18m`. What area of the ground can be photographed by this camera in a single shot?

Explanation

`-u=2000m " " f=0.50m`
Size of the image `0.18m xx 0.18m`
Using the formula, `(1)/(f)=(1)/(v)-(1)/(u)`
We get, `(1)/(0.50)=(1)/(v)+(1)/(2000), v=0.50m`
`therefore` Image will be formed at the focus.
`m=(v)/(u)=(0.5)/(2000)=0.00025`
`therefore ` Size of the object on the ground will cover an area of `(0.18)/(0.00025)xx(0.18m)/(0.00025)`
i.e., Area on the ground `=720m xx 720m`.