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Electricity EMF and Internal Resistance question

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Reply 20
Avatar for thefatone
thefatone
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Original post by samb1234
It works exactly the same for the internal resistance, you can just use a standard power formula. If you don't already know them, it would be worth getting comfortable with using p=I^2 R and p=v^2 /R as they make the written questions much easier


i don't know which values to use
Original post by thefatone
i don't know which values to use


p=I^2 R (would always use in this situation as it is a series circuit so by definition current is same everywhere, so don't have to do any extra calculations). So basically for the power lost due to internal resistance p=I^2 r where r is internal resistance
Reply 22
Avatar for thefatone
thefatone
OP
6
Original post by samb1234
p=I^2 R (would always use in this situation as it is a series circuit so by definition current is same everywhere, so don't have to do any extra calculations). So basically for the power lost due to internal resistance p=I^2 r where r is internal resistance


oh right i used the wrong value of resistance xD
Reply 23
Avatar for thefatone
thefatone
OP
6
Original post by samb1234
p=I^2 R (would always use in this situation as it is a series circuit so by definition current is same everywhere, so don't have to do any extra calculations). So basically for the power lost due to internal resistance p=I^2 r where r is internal resistance


pd across terminals of a cell was 1.1v when current is 0.2A and 1.3v when current was 0.1A
how do i find internal resistance of cell and emf?
Original post by thefatone
pd across terminals of a cell was 1.1v when current is 0.2A and 1.3v when current was 0.1A
how do i find internal resistance of cell and emf?


Vt=emf-ir

solve simultaneously with 2 different currents
Reply 25
Avatar for thefatone
thefatone
OP
6
Original post by samb1234
Vt=emf-ir

solve simultaneously with 2 different currents


ok thanks

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