All things being equal, will one 100-watt light bulb or two 50-watt light bulbs make a room look brighter?

Then evaluate whether the room is bright or not the parameter should be the illuminance (unit is lux, lx), that is, the luminous flux divided by the area, 1lx=1lm/1㎡. Sunny noon outdoor illuminance can reach 80000-120000lx, cloudy noon outdoor 8000-20000lx (recently in the entanglement can use illuminance to make cloudy judgment), equipped with 40W incandescent lamp under the desktop illuminance average of about 200-300lx, illuminance can be linear superposition.

Since the luminous principle of ordinary lamps and energy-saving lamps is to heat and then glow, so as for a 100W and two 50W ordinary or energy-saving bulbs which lumen is high, I feel that it depends on the lamp filament temperature.

If the peak of the radiation characteristic curve of 100w filament temperature is concentrated in yellow-green light (wavelength around 560-600nm) (cause: People are the most sensitive to yellow and green light, the lumens mentioned earlier are based on the amount of light felt by the human eye, so the luminous flux caused by yellow and green light is large, and the wavelength of 555nm yellow and green light is also used to define the luminous flux), then the 100W bulb can emit the maximum luminous flux, in the case of the same room area, the illuminance is the largest.

If the luminous heat ratio of two 50w bulbs is the same as that of 100w, it also depends on the filament temperature, because the illuminance can be linearly superimposed, so the two can optimally make some parts of the room look as bright (some other locations involve the uniformity of light, not discussed).