Question

The screen of a pinhole camera is a square, of side 0.16m and it is 0.15m behind the pinhole. The camera is placed11m from a flag staff and positioned. The image occupies three-quaters of the height of screen. What is the height of the flag staff? What is the disadvantage of a pinhole camera compared to a lens camera.

Answer 1

$\frac l{0.75h}=\frac ab,$

$l=\frac{0.75ah}b=8.8~m .$