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    I have this question that i dont understand:
    A 36W lamp draws a constant current of 3.0A over a period of 600s from a battery. Calculate the number of electrons passing through the lamp.

    I have already worked out: the p.d across the lamp= 12V
    the energy transferred by the lamp= 21600J
    the charge passing through the lamp= 1800C

    thanks in advance
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    1A = 1 coulomb per second, so for 3A in 600s how many coulombs?
    Then 1 coulomb = how many electrons? (remember - 1 elementary charge = 1.602x10^-19 C)
    Multiply these together and you're sorted.


    I think
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    (Original post by alex193)
    ***
    I see this is your first post in the physics study help section.
    Thanks for helping.

    However...
    Can I direct you to the guidance notes for posting here
    http://www.thestudentroom.co.uk/wiki...ring_questions

    in particular the request not to provide complete solutions to numerical problems. The aim is to help the poster help himself. As he had almost got to the solution, a small prod in the right direction was all that was needed.
    Thanks for your cooperation.
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    Oops, should probably have read that first :ashamed2:
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    (Original post by alex193)
    Oops, should probably have read that first :ashamed2:
    There may still be time to edit your post and simply delete the last line.
 
 
 
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Updated: March 11, 2013
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