Physics level 3 help

How do I calculate the Power lost by internal resistance? Please help.
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Hi Samuel,

Good question.

We will represent the internal resistance as if it were a resistor. Normally you would be given, or be able to calculate two or more quantities relating to this ‘resistor’:

  • the current through this resistor

  • the voltage drop across this resistor

  • the resistance of this resistor

Given two of those, you should be able to use P=IV, P=I^2R, or P=V^2/R to calculate the power of the resistor.

There are a couple of alternative ways you could work it out, but I think the above would be a more likely approach for a L3 Physics paper.

If you’d like to post the question, and any relevant values, I’ll post a solution.