Question

State the effect on the image in a pinhole camera if the luminous object is moved towards the pinhole.

Answer 1

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

From the above relation we can say that distance of object from pin hole is inversely proportional to size of image. Hence, if the luminous object is moved towards the pinhole ($d_o$ decreases), the size of the image ($h_i$) increases.