How do you convert lux to Em-2s-1?

Answer 1

To convert lux (lx) to irradiance in watts per square meter (W/m²), which is equivalent to energy flux density in joules per square meter per second (J/m²·s or Em⁻²s⁻¹), you can use the formula:

[ \text{Irradiance (W/m²)} = \text{Lux} \times \frac{1 \text{ W/m²}}{683 \text{ lm}} ]

This conversion accounts for the luminous efficacy of light, which is approximately 683 lumens per watt for visible light. Thus, multiply the lux value by 0.001464 to get the result in Em⁻²s⁻¹.