explain construction &working of a pinhole camera
A pinhole camera is a simple optical device that forms an image without using a lens or a mirror.
Construction of a Pinhole Camera
Take two cylindrical pipes, so that one can slide into another with no gap in between them. Cut open one side of each pipe. On the opposite face of the larger pipe, make a small hole in the middle. In the smaller pipe , cut them from the middle a square with a side of about 5 to 6 cm. Cover this open cylindrical pipe with a tracing paper. Slide the smaller pipe inside the larger pipe with a hole in such a way that the side with the tracing paper is inside.
Here is a graphical representation of a simple pinhole camera.
Working principle of a Pinhole Camera
The size and contrast of the formed image can be changed by sliding the smaller cylinder. In addition, the image also depends on the size of the pinhole; the smaller the pinhole, the sharper will be the image and vice-versa.
Try looking at your own hand through a pinhole camera. You will observe an upside down image of your hand.
A pinhole camera creates a real image of an object, because the image can be captured on a screen. The image formed by a pinhole camera is inverted and smaller than the object.
Construct your own pinhole camera and look at the sun during a solar eclipse. Avoid looking at the sun directly.
In the pinhole camera when the light rays are reflected of an object and to the glace paper in the pinhole camera,the rays of the top of the object are reflected below than the rays of the bottom of the object through the pinhole and to the paper so we see it upside down and the far we take the smaller box out light rays get more separated and hence bigger image is formed