A common unit of illumination intensity is called a footcandle and is equal to
A) the amount of light one foot away from a candle.
B) the amount of light from a one-foot long candle.
C) one lumen distributed over an area of 1-square-foot.
D) none of the above

Question

Quizplus · Accepted Answer

A footcandle is defined as the amount of light that falls on a surface one foot away from a standard candle that emits light with a luminous intensity of one candela. This is equivalent to one lumen of light distributed uniformly over an area of one square foot. Therefore, option C is the correct answer.

A Common Unit of Illumination Intensity Is Called a Footcandle