Power Dissipation

Discussion in 'Homework Help' started by tjjam2003, Apr 7, 2006.

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  1. tjjam2003

    Thread Starter Member

    Apr 5, 2006
    22
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    If a resistor of 350 ohms is connected across a source of 175 volts, with a current of 0.05 amps what is the power dissipation?? It should be 87.50W right??

    What if the voltage is reduced to 105 volts, what is the power being dissipated by the resistor??

    The answer in the book says : 31.5W

    I'm not sure how they got that answer, how do I write it out to get the answer??


    Thanks !!!
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,140
    1,790
    You must have been typing a bit fast. 175 volts on 350 ohms is 0.5 amperes, not 0.05 and yes that woul be 87.5 Watts. A substantial power resistor!

    Twinkle twinkle little star
    Power's equal I squared R
    Code ( (Unknown Language)):
    1.  
    2. I = E/R implies 105/350 = 0.3 Amperes
    3.  
    4. (0.3)*(0.3)*350 = 31.5 Watts
    5.  
    6. Also
    7.  
    8. P = E^2/R = ((105)*(105))/350 = 31.5
    9.  
    What kind of book gives you a problem, and does not show you how they got the answer? May be time for a new book!
     
  3. paultwang

    Well-Known Member

    Mar 8, 2006
    80
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    Edit: Papabravo has answered your question.
     
  4. tjjam2003

    Thread Starter Member

    Apr 5, 2006
    22
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    Thanks...I'm sure I'll be back with another one.
     
  5. Papabravo

    Expert

    Feb 24, 2006
    10,140
    1,790
    Gee paultwang,

    You could have left your answer up, after all you went to the trouble of creating it, and a second opinion or viewpoint never ever hurts.

    cheers
     
  6. bk123

    New Member

    Nov 24, 2014
    5
    0
    If a 10 ohm resistance is connected to an a.c voltage of 100 sin(314t + 30deg), the power dissipated is?
    kindly reply
     
  7. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,346
    Hello,

    Please start a new thread in stead of digging old threads.

    Bertus

    PS closed due to old age
     
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