Question

A man 2m tall stands 3m from a pinhole camera how is the image in the camera affected when the man moves 1m closer to the camera

Answer 1

The image in the camera will be affected and will increase in size as the man moves 1 m closer to the camera.

• The equation in optics to determine this is given by:- ho/do = hi/di

        Where, ho and do are object height and distance and hi and di are image parameters.

• Therefore, as object distance decreases the image size will increase.
• And hence the image will increase in size in the above scenario.

Answer 2

A man 2 m tall stands 3 m from a pinhole camera.  When the man moves 1 m closer to the camera, the image in the camera increases in height.  

• In a case of a pinhole camera,

         $\frac{I}{O} = \frac{v}{u}$

• Here, I is the height of the image, O is the height of the object, v is the distance of the image from the pinhole camera and u is the distance of the object from the pinhole camera.
• As evident from the equation, the object distance from the pinhole camera is inversely proportional to the height of the image.
• So, when the man moves closer, that is, the distance of the object from the pinhole camera decreases, the height of the image increases.