Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    0
    ReputationRep:
    a 100W light bulb is plugged into a standard 120V outlet. how much does it cost per month (31 days) to leave the light turned on? assume electricity costs 6 cents per kw.h What is the resistance of the bulb? what is the current in the bulb?
    Offline

    20
    ReputationRep:
    the watt is a unit of power, the hour is a unit of time.

    power is a rate of doing work i.e. Energy/time

    so multiply watts by hours and you get kWh which is a unit of energy (i.e. what you are being charged for when the electric company sends you an energy bill)

    it's not an SI unit of energy but can be converted to one easily enough because 1Joule = 1 Watt second

    how many seconds in 1 hour?
    how many Watts in 1 kW?
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Has a teacher ever helped you cheat?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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

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