2023-02-23 17:44

Lumen (symbol lm) is the international unit of luminous flux. It is defined according to the candela spherical angle (cd times sr). One lumen is a considerable amount of light emitted in 1 spherical angle unit, which emits equal amount of energy from the light source in all directions, and the intensity is 1 cd.

One lumen is equal to the electromagnetic energy (EM) radiated by 1.46 milliwatts (1.46 x 10 ^ - 3W) at 540 terahertz (540 THz or 5.40 x 10 Hz). Reduced to SI basic unit, 1 lumen is equal to 0.00146 kg square meters per second to the third power (1.46 x 10 kg times m/s).

Lumens are a small unit. The electromagnetic force level of 1.46 milliwatts is very small. The radio frequency (RF) output of children's toy two-way radio is several times that of it. The frequency of 540 THz corresponds to a wavelength of about 556 nanometers (nm) in the visible light spectrum. The spherical angle is a fixed angle in three dimensional standard units; The sphere contains four pi (approximately 12.57) spherical angles.