question_answer

An object 2.5 m high is placed in front of a pin hole camera. If the width of camera is 24 cm and size of image formed is 1.2 cm, find the distance of the object from pin hole camera.

Answer:

Size of object,\[O=2.5\text{ }m=250\text{ }cm\] Width of pin hole camera, \[v=24\text{ }cm\] Size of the image,\[I=1.2\text{ }cm\] Object distance,\[u=?\] We know that, \[m=\frac{v}{u}=\frac{I}{O}\Rightarrow \frac{v}{u}=\frac{I}{O}\]On substitution, we get, \[u=50000cm=50\text{ }m.\]