Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-l] light bulbs


On 2011, Mar 08, , at 05:55, Fakhruddin, Hasan wrote:

I agree with Joshua Gates. Moreover, 60 W rating most probably includes amount of heat generated and to a lesser extent higher and lower wavelengths ... remember the Black Body radiation curve?!


I've never read otherwise. All the lamps to which I've compared the advertised and measured agreed w/in a few %.


bc

p.s. the term you desire is efficacy.

p. 201's (Levi 1968) graph shows, inter alia, the efficacy and luminous flux for typical N2 filled incandescents. All the curves, except life, intersect the 100 percent normal volts. At 50 % V, the efficacy is ~ 20% Lumens / W and the Lumens is sl. < 10%.