Question

State the effect on the image in a pinhole camera if the length of the pinhole camera is increased (i.e., screen is moved away from the pin hole).

Answer 1

We know,
$\frac{h_i}{h_o}=\frac{d_i}{d_o}$
$h_i=sizeofimage$
$h_o=sizeofobject$
$d_i=distanceofscreenfrompinhole$
$d_o=distanceofobjectfrompinhole$

As the length of the pinhole camera ($d_i$) is increased, the distance of the screen from the pinhole increases.

So, the size of the image ($h_i$) increases. Hence, when the length of the pinhole camera is increased, the size of the image increases.