EMF's in series how does this work ?

[hilly]

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 voltage of the cells. Calculate the voltmeter reading and the current in each cell.

Ans given by book:72.8mA, 34.3mA, 1.93V

Homework Equations

Kirchoff voltage law.

The Attempt at a Solution

I can not understand how 2 cells in series can have a different current ? What concept am I missing ?

 

[zeitghost]

The current will change according to which cell voltage you are measuring.

The voltmeter has a resistance of 50R... (that's some "voltmeter"...)

 

[Defennder]

Is there a picture for the question? I'm not sure how the voltmeter is connected to measure the terminal voltage.

 

[hilly]

Is there a picture for the question? I'm not sure how the voltmeter is connected to measure the terminal voltage.

Sorry no picture because the textbook has no picture only the words

 

[hilly]

The current will change according to which cell voltage you are measuring.

The voltmeter has a resistance of 50R... (that's some "voltmeter"...)

The book answer gives one voltage and 2 currents.

 

[Redbelly98]

Instead of thinking about 2 batteries in series, try picturing the situation as 3 objects all in parallel (the 2 cells and the 50-ohm resistor).

Don't forget to include the internal resistances as part of the cells.