Two cells in series with internal resistors -- calculate the current

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SUMMARY

The discussion centers on calculating the current in a circuit with two cells in series, each having internal resistors. Participants emphasize the importance of accurately representing the circuit diagram to apply Ohm's Law (V=IR) effectively. The original poster (OP) struggles with the concept of differing currents in the circuit, which is clarified by the need to consider the resistance of the voltmeter and the correct connections between the cells. A proper circuit diagram is essential for resolving the confusion and achieving an accurate calculation.

PREREQUISITES
  • Understanding of Ohm's Law (V=IR)
  • Familiarity with circuit diagrams and schematic representation
  • Knowledge of series circuits and internal resistance concepts
  • Basic principles of voltage and current measurement
NEXT STEPS
  • Research how to draw and interpret circuit diagrams accurately
  • Learn about the effects of internal resistance in batteries
  • Study series circuits and current distribution in electrical components
  • Explore the role of voltmeters in circuit analysis and their internal resistance
USEFUL FOR

Students studying electrical engineering, hobbyists building circuits, and anyone seeking to understand the principles of current flow in series circuits with internal resistances.

lalallaland
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Homework Statement
A secondary cell having an e.m.f. of 2V and an internal resistance of 1ohm is connected in series with a primary cell having an e.m.f. of 1.5V and an internal resistance of 100ohm the negative terminals of each cell is connected to the positive terminal of the other cell. A voltmeter having a resistance of 50ohm is connected to measure the terminal volatage of the cells. Calculate the voltmeter reading and the current in each cell.

Ans given by book:72.8mA, 34.3mA, 1.93V
Relevant Equations
Kirchhoff law
Can somebody explain this please? I don't understand this.
 
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Welcome to the PF.
lalallaland said:
Can somebody explain this please? I don't understand this.
How about you draw the circuit as described and attach it to a reply? Label the voltages and resistances in the loop, and show us how you can use the equation V=IR to work toward the answer. (We aren't allowed to provide tutorial help here until you show your best efforts). Thanks
 
Hey Berkeman,

Thanks a lot for your answer. I'm really stuck at this problem and it is not leaving my mind. I don't really know how to use V=IR here cause the answer tells me there are two different currents.
 

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lalallaland said:
the answer tells me there are two different currents.
You are given the resistance of the voltmeter. What does that imply?
 
However the circuit you supplied does not match that description.

Could you explain this statement? Because I think my circuit matches the description.
 
If I am reading your circuit correctly, the negative terminal of the 1.5V cell is correctly connected to the positive of the 2V cell. The negative of the 2V cell is connected to ... Where?
 
It's very helpful to actually display text and/or graphics being referred to. Here is the circuit given by OP.
1569731019165.png
 
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