Power and heaters

  1. 1. The problem statement, all variables and given/known data
    A heater rated at 2000W operating at 250V is used on a supple of 230V. if the resistance of the heater will not be affected by temp, what is the power absorbed by the heater?


    2. Relevant equations
    i think that the only equation to use will be P=V^2/R


    3. The attempt at a solution
    because the resistance of the heater is its internal property, i would first compute for the resistance from: R=(230^2)/2000. afterwhich, i would compute the power absorbed by the heater through: V=250-230=20 -> P = (20^2)/R which will be computed from the previous equation. is this right?

    thanks!
     
  2. jcsd
  3. Redbelly98

    Redbelly98 12,040
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    Not quite. At 230 V, the power will be different than 2000 W.

    So, P is 2000W when V=?
     
  4. oh sorry. so, i think it shouldve been R=V^2/P and V=250V while P=2000W.

    so, the power when it operates at 230V is simply P= 230^2/R and the answer I would subtract from 2000W? is it right? thanks
     
  5. Redbelly98

    Redbelly98 12,040
    Staff Emeritus
    Science Advisor
    Homework Helper

    Yes, correct up to this point.

    Uh, no. The problem statement asks for the power when V=230V. So just use the power you get from
    P= 230^2/R​
    ... and that's the final answer.
     
  6. lol, i misinterpreted the question. thanks, really!!!:D
     
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