Resistors in Series - Lab data confusion

[CWatters]

How did you calculate the resistance with those current values?

In a series circuit, the current value is supposed to stay the same, and the voltage value is supposed to vary.

That's what got me thinking that you didn't have all three resisters in series when measuring the current through each resistors . If you changed the circuit and connected each resistor on it's own to the power supply (or put them all in parallel) then the voltage would be the same each time and the current values would change. The calculated current values are very close to the figures you measured if you allow for the mA vs A error.

So using your data with the current corrected to mA...

R1 = 5.06/(50.2 * 10^-3) = 100.8 Ohms
R2 = 5.03/(23.0 * 10^-3) = 218.7 Ohms
R3 = 5.05/(10.9 * 10^-3) = 463.3 Ohms

Which are close to the correct values.

 

[CWatters]

I see you have another thread on the same/similar subject..
https://www.physicsforums.com/threads/resistors-in-series-lab-data-confusion.924626/

 

[shmoop]

That's what got me thinking that you didn't have all three resisters in series when measuring the current through each resistors . If you changed the circuit and connected each resistor on it's own to the power supply (or put them all in parallel) then the voltage would be the same each time and the current values would change. The calculated current values are very close to the figures you measured if you allow for the mA vs A error.

So using your data with the current corrected to mA...

R1 = 5.06/(50.2 * 10^-3) = 100.8 Ohms
R2 = 5.03/(23.0 * 10^-3) = 218.7 Ohms
R3 = 5.05/(10.9 * 10^-3) = 463.3 Ohms

Which are close to the correct values.

Yes, I believe you are very correct. I must have disconnected the series circuit in the process of attempting to measure the voltage drops.

Thanks a lot for your input!

 

[shmoop]

Now you could redo the math using your actual resistor values
you should again end up with 5V ( as a total drop) give or take a couple of decimal points

each individual drop will be a little different to what you just worked out for the ideal resistor values

Thank you very much! You were a great help in having me figure out what my voltage drops were. I appreciate it

 

[FactChecker]

You can read the resisters by their color codes or you can measure them one at a time, stand alone. That will help greatly. For resisters in series there are three important things to consider that your data has completely wrong:
1) The current through all resisters will be equal.
2) The voltage drop over any resister is proportional to the resistance.
3) The total voltage drop is the sum of the individual voltage drops across the resisters.

You should make sure that your measurements agree with these principles for resisters in series before you precede.