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Homework Help: Current electricity

  1. Dec 2, 2005 #1
    I am revising the chapter on current electricity and i came across this question which i got stuck in the last part. It shows a circuit with a thermistor having a resistane of 60k ohms at 100 deg C and 100k ohm at 0 deg C. The termistor is in series witha 12 k ohm resistor There is a voltmeter but we are told that we can consider it behaving ideally. Now the last questions were: depermine the power dissipated in the thermistor at
    a 100 deg C
    b 0 deg C

    Checking my answer for a , it was worked out rigght :). but d problem is b, i got a wrong ans when I used the same method ie

    I found R total by adding the 2 resistances. Then using ratios I found voltage across the thermistor which is 10.7, then using I=V/R i found I and then used P=IV. What is wrong pls? My book says that the ans is 4microwatts
  2. jcsd
  3. Dec 2, 2005 #2


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    Homework Helper

    You are most likely using the wrong value for voltage or current at some stage. If you could write out your calculations.

    One method in doing the problem is to find the total resistance, then find the total current. To find the power dissipating through any resistor, then use [tex]P_1 = I^2 R_1[/tex].
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