The flux of light received in a unit area of a certain side being shown is popularly known as illumination. The measuring unit in both United Kingdom and America is known as footcandles light, but in Europe it is also known as meter candlelight.
One foofcandles light is the illumination of light that falls on one side which is one foot away from a one foot-candlelight and exactly intersecting with the light. Its abbreviated form is written as 1 Fc=1 Lm/ft, similarly, one-meter candlelight is the illumination of light that falls on a side which is one meter away from a one meter candlelight and exactly intersecting the light. lt is also called Lux i,e. the flux of light being received in each sq. meter is called the illumination of one lumen.