Explain the working principle of a pinhole camera. Why is the image formed in a pinhole camera always inverted?
A pinhole camera works on the principle that light travels in straight lines. It consists of a light-proof box with a tiny hole (pinhole) on one side and a translucent screen on the opposite side. When light from an object passes through the pinhole, it forms an image on the screen. The image formed by a pinhole camera is always inverted because light rays from the top of the object travel downwards through the pinhole to the bottom of the screen, and light rays from the bottom of the object travel upwards through the pinhole to the top of the screen. This crossing over of light rays at the pinhole causes the image to be upside down and laterally inverted.
Explanation
Key points for grading: Explanation of light travelling in straight lines through the pinhole. Description of how light rays from different parts of the object cross at the pinhole, leading to an inverted image. Mentioning the components (box, pinhole, screen).