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Calculate the efficiency of the LED bulb? Watch

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    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?
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    Empirically. You've got to measure the thing unless you're given more information.
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    (Original post by Lumi172)
    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?
    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.
 
 
 
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