ABSTRACT
Light is that portion of electromagnetic spectrum that is responsible for the sense of seeing. Light can be produced by suitable conversion of other forms of energy. Nuclear reactions at the core of the sun and the other stars produce an almost inexhaustible supply of light energy. Artificially, light is produced by heating, electrical discharge, electrical current injection, etc. Since our visual experiences are due to light, and since also many physical processes can be understood by the light generated, the measurement or quantification of light is essential [1–3].
