If a 60W light bulb in a bedside lamp is only 20 percent efficient in converting electric energy into light en?

If a 60W light bulb in a bedside lamp is only 20 percent efficient in converting electric energy into light en?
if a 60W light bulb in a bedside lamp is only 20 percent efficient in converting electric energy into light energy, how much joules of light energy does the light bulb produce each minute.

Light energy = 60 J/s * 0.20 * 60 = 720 J / min

This entry was posted on Saturday, January 30th, 2010 at 7:37 am and is filed under bedside lamps. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

2 Responses to “If a 60W light bulb in a bedside lamp is only 20 percent efficient in converting electric energy into light en?”

hobart_elf on January 30th, 2010 at 1:23 pm

Work = Power x time

Work is in Joules (which is Watts per second)

Power is in Watts

time is in seconds.

The electricity-to-light conversion efficiency is irrelevant here. Whatever the efficiency is (20% seems the usual) the lamp is still consuming 60 Watts.

W = P.t

= 60 x 60

= 3600 Joules/minute

References :
Al P on January 30th, 2010 at 1:38 pm

Light energy = 60 J/s * 0.20 * 60 = 720 J / min
References :

Everything Lamps