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Dissipated power

  • Thread starter miew
  • Start date
  • #1
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Homework Statement


You are given a number of 10 resistors, each capable of dissipating only 1.0 W without being
destroyed. What is the minimum number of such resistors that you need to combine in series or
in parallel to make a 10 resistor that is capable of dissipating at least 5.0 W?


Homework Equations





The Attempt at a Solution


I don't understand the problem. I can't see how the final resistance can be 10 if there is more than one resistor. But at the same time I don't get how the power can be 5 with just one..

Help please, we haven't really seen this in class.
 

Answers and Replies

  • #2
ehild
Homework Helper
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Start with 4 resistors. What is the resultant resistance of two parallel resistors each of resistance R? And what happens if you connect two such pairs in series?

ehild
 
  • #3
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OKay, so i got the resistance (I was doing wrong calculations) but I don;t get the power to be 5 but 4 W...
 
  • #4
ehild
Homework Helper
15,493
1,875
Try connecting more resistors. You need 5 at least.


ehild
 
  • #5
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I got it now ! thank you :)
 

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