Join TSR now and get all your revision questions answeredSign up now

Calculate the efficiency of the LED bulb?

    • Thread Starter
    Offline

    0
    ReputationRep:
    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?
    Offline

    3
    ReputationRep:
    Empirically. You've got to measure the thing unless you're given more information.
    Online

    3
    ReputationRep:
    (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.
 
 
 
Poll
Do you have exam superstitions?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.