Finding the emf and internal resistance of a cell

AI Thread Summary
The discussion focuses on a proposed experimental method to determine the electromotive force (EMF) and internal resistance of a cell with known parameters. The experiment involves using the equation ε=Ir+IR, rearranging it to V=-Ir+ε, and plotting the results to find the EMF and internal resistance from the graph's intercept and gradient. The method includes adjusting a rheostat to obtain multiple voltage and current readings without exceeding 1.5 amps. Feedback indicates that the proposed method appears sound and aligns with the theoretical framework. Overall, the approach is deemed appropriate for the coursework objective.
dtwazere
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I hope someone can help me with my coursework by making sure my method is ok and is actually correct for my experiment. Note. I will not actually be doing this it is just a plan of what I could do!

1. I am provided with a cell of approcimate EMF 1.5V, an approximate internal resistance of 1Ω and an approximate energy capacity of 1.5Ah. I have to plan an experiement to find the EMF and internal resistance.



2. I know that i will be using the equation ε=Ir+IR and rearranging it to give V= -Ir +ε and linking it with the general equation for a linear graph y=mx+c. I know the y intercept will be the EMF and the gradient, -r, will be my internal resistance.



3. For my method i will be setting up my experiment like this:http://img232.imageshack.us/img232/774/experimentma5.th.jpg

I want to know if my method is correct. I will turn on the cell and adjust the rehostat until i find the lowest current recorded on my ammeter. I will then read off my voltage and make a table of both readings. I will then adjust the rheostat each time so I take 10 readings of voltage and current but i will not exceed 1.5 amps. Does this method seem ok? I am confused on whether it is correct or not.

Thanks in advance for your help,

Daniel

 
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Seems pretty all right to me.
 
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