illumination

the flow of light or light flux which is measured in lumens

the light leaving the surface which has been illuminated the source

the light source has a luminous intensity and is measured in candela

the light energy radiated out per second from the body in the form of luminous light waves

unit of luminous flux

a point source in any particular direction is given by the luminous flux radiated out per unit solid angle in that direction. in other words, it is a solid angular flux density of a source in a specified direction.

when light falls on a surface the level of illumination on that surface is referred to as . the unit of measurement is lux

the unit of luminous intensity and is approximately equal to one candle power.

the average candle power of a source is the average value of its candle power in all directions.

if the average is taken over a hemisphere instead of a sphere then this average candle power is known as