The inside of optical instruments like camera and telescope are blackened. Explain.

Explanation

When light is incident on an object of black colour the light is not reflected and most of the light is absorbed by the object. If the inside of an optical instrument is not blackned, then the light will be reflected from the parts inside the instruments and it will overlap with the imege. Hence the image will become blurred. Thus if the inside of the optical instrument is blankned, then there if no unwanted reflection of light and the instruments can function property.