One foot-candle is equivalent to how many lumens?

One foot-candle is equivalent to how many lumens?

• A. 1.0 lumen
• B. 10.76 lumens
• C. 100 lumens
• D. 0.1 lumen

Answer: (B)

Foot-candle is a measure of illuminance—how much light lands on a surface—expressed as lumens per square foot. Lumens, on the other hand, are the total amount of light emitted or received, not per unit area. To convert illuminance to total lumens, multiply by the area illuminated. Relating feet and meters helps here. 1 fc equals about 10.764 lux, and 1 lux is 1 lumen per square meter. Therefore, if you illuminate a 1 square meter area at 1 fc, the total light in lumens is 10.764 × 1 m^2 ≈ 10.764 lumens. Rounded, that’s about 10.76 lumens. This is why the correct value is around 10.76 lumens.

Foot-candle is a measure of illuminance—how much light lands on a surface—expressed as lumens per square foot. Lumens, on the other hand, are the total amount of light emitted or received, not per unit area. To convert illuminance to total lumens, multiply by the area illuminated.

Relating feet and meters helps here. 1 fc equals about 10.764 lux, and 1 lux is 1 lumen per square meter. Therefore, if you illuminate a 1 square meter area at 1 fc, the total light in lumens is 10.764 × 1 m^2 ≈ 10.764 lumens. Rounded, that’s about 10.76 lumens. This is why the correct value is around 10.76 lumens.