The brightness-producing capability of a source

Step-by-step solution

The brightness-producing capability of a light source is determined by its luminous flux, which measures the perceived power of light. The human eye is not equally sensitive to all wavelengths of light. The sensitivity is maximum for a wavelength of 555 nm (yellow-green region) and decreases for other wavelengths. Thus, the brightness depends on the emitted wavelength. Additionally, for a specific wavelength, a source emitting more radiant energy per unit time (radiant power) will produce a greater visual sensation