An object of height 250m is placed in front of a pinhole camera at a distance of 100cm. Calculate the magnification if image distance is 10cm.

The object distance ($u$) is $40 \text{ cm}$.
The image distance ($v$) is $7.5 \text{ cm}$.

The magnification ($M$) for a pinhole camera is given by the ratio of the image distance to the object distance:

The magnification is a dimensionless quantity.

The final answer is 0.1875.