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Calculate the efficiency of the LED bulb?

I have the power input in watts which is 5 and the lifetime in hours which is 50,000. The efficiency is left blank and I have no idea how I calculate it. Having a hard time with physics... Anyone know how to work it out?

Reply 1

mik1a

Empirically. You've got to measure the thing unless you're given more information.

Reply 2

Joinedup

Original post by Lumi172

Not clear what you've been asked to do.

Consumer packaging on bulbs gives a measure of light output called lumens - if I was out shopping for lightbulbs I'd calculate the lumens per watt.