SI Units

Lux

Definição

A unidade de iluminância do SI, medindo o fluxo luminoso recebido por unidade de área: um lux equivale a um lúmen por metro quadrado (1 lx = 1 lm/m²).

Explicação

Direct sunlight delivers about 100,000 lux; an overcast sky provides 1,000 lux; office lighting is typically 300–500 lux; a full moon produces roughly 0.25 lux. The key difference from lumens: lumens measure total light output from a source, while lux measures how much of that light reaches a surface. Moving a lamp twice as far away reduces illuminance by a factor of four (inverse-square law).

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RELATED TERMS

Metro

A unidade de comprimento de base do SI, definida como a distância que a luz percorre em 1/299.792.458 de segundo.

Quilograma

A unidade de massa de base do SI, definida por meio da constante de Planck.

Segundo

A unidade de tempo de base do SI, definida com base nas oscilações do átomo de césio-133.

Kelvin

A unidade de temperatura termodinâmica de base do SI, cujo ponto de origem é o zero absoluto.

Ampere

A unidade de corrente elétrica de base do SI.