2006-11-14 13:55:17 · 7 answers · asked by John B 2 in Science & Mathematics ➔ Physics
120W would be brighter, and here is why:
120W light bulb would have higher temperature (rough argument: dQ/dt= c*m-sigma*T^4, at equalibrium c*m = sigma*T^4 =P =V*I, where c= heat capacity per mass), and by Planck's law of black-body radiation will emitt more visible light than Infra Red light, so it's more efficient in producing visble light for the same energy than 2x 60W light bulbs. Great question.
2006-11-14 14:08:59 · answer #1 · answered by justiceforall 2 · 0⤊ 0⤋
IF the bulbs operated at the same efficiency - converting the power used to visible light - (as low as a 5% efficiency in some incandescent lamps) - the brightness will be the same.
However, this is not the case.
A 60W bulb produces approximately 850 lumens (about 14.2 lm / W) while a 120W bulb produces approximately 2064 lumens (or 17.2 lm/W).
A 120W bulb doesn't just seem brighter than two 60W bulbs...........the 120W bulb is brighter than two 60W bulbs (2064 lm vs. 1700 lm)
2006-11-14 22:37:52 · answer #2 · answered by LeAnne 7 · 0⤊ 0⤋
I think 120 is brighter.
2006-11-14 22:07:08 · answer #3 · answered by too4barbie 7 · 0⤊ 0⤋
There is the same amount of power consumed in either case, the first probably appears brighter since it is coming from a single point.
2006-11-14 21:59:08 · answer #4 · answered by Chris J 6 · 1⤊ 1⤋
i think 120 watt light bulb???..... not sure!
2006-11-14 22:04:22 · answer #5 · answered by s.o.s 2 · 0⤊ 0⤋
it would be the same thing,120 is 120!!
2006-11-14 22:03:31 · answer #6 · answered by kitty 4 · 0⤊ 2⤋
kinky.
2006-11-14 22:02:24 · answer #7 · answered by John16 5 · 0⤊ 3⤋