Hello Kamlesh, 

A camera is an optical instrument to capture images or to record mov8ng images, which are stored in a physical medium such as in a digital system or on phitographic film. A camera consists of a lens which focuses light from the scene, and a camera body which holds the image capture mechanism.

There are different megapixels available in market in cameras the higher the megapixel more the clarity in the image. 

Cameras are used in our day to day life for various uses and helps us a lot. 

Hope the information would have helped you.