# 3 batteries in parallel

#### qety6321

1. The problem statement, all variables and given/known data
two batteries A and B are connected in pareallel. A has emf of 108V and internal resistance of 3 Ω while B has emf of 120V and internal resistance of 2Ω. The battery terminal is connected to battery C in series with a 25 resistor. Battery C has emf of 30V and negligible internal resistance.

2. Relevant equations
find the value and direction of current in each battery and terminal voltage of B.

3. The attempt at a solution
I'm struggling to find the current in each battery first and I have tried to find the terminal voltage of B by using Kirchhoff's law and nodes but cannot get the right answer.

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#### NascentOxygen

Mentor
Hi qety6321. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif [Broken]

Please attach your sketch of the circuit showing all the information given. Then show your calculations so we can see where you are going wrong.

Last edited by a moderator:

#### berkeman

Mentor
1. The problem statement, all variables and given/known data
two batteries A and B are connected in pareallel. A has emf of 108V and internal resistance of 3 Ω while B has emf of 120V and internal resistance of 2Ω. The battery terminal is connected to battery C in series with a 25 resistor. Battery C has emf of 30V and negligible internal resistance.

2. Relevant equations
find the value and direction of current in each battery and terminal voltage of B.

3. The attempt at a solution
I'm struggling to find the current in each battery first and I have tried to find the terminal voltage of B by using Kirchhoff's law and nodes but cannot get the right answer.
As a bonus question, calculate how long before one of the batteries catches fire...

#### Chronum

Try drawing the EMF ups and downs separately for the batteries. Something like a ----EMF---/\/\/---- diagram. Then use appropriate math.

"3 batteries in parallel"

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