How Do You Calculate Resistance in a Series Circuit?

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The discussion centers on calculating resistance in a series circuit with a 9V power supply and a current of 300mA. The total resistance is established as 30 Ohms, leading to the conclusion that each resistor, when two are present, would have a resistance of 15 Ohms. The conversation also highlights the importance of accurately interpreting circuit diagrams and the implications of including inductors without proper context.

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_________300ma__
|...... |
|...... ∏ L1
_ +......| R1
9v......|........ ignore the dots in the middle
- -...... ∏ L2
|......| 2R
|________________|

Find the:

The value of R

The total resistance

and any other answers this question might yield

Thanks a lot.

only question i got wrong in a test. :(
 
Last edited:
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300ma = 9/R
Total Resistance = 30Ohms

30/2 = 15ohms each resistor?
 
lazyboy92 said:
_________300ma__
|...... |
|...... ∏ L1
_ +......| R1
9v......|...... ... ignore the dots in the middle
- -...... ∏ L2
|......| 2R
|________________|

Find the:

The value of R

The total resistance

and any other answers this question might yield

Thanks a lot.

only question i got wrong in a test. :(
I am redrawing the circuit, hopefully this is easier to look at:
Code:
 ________300ma__
|               |
|               ∏ L1   
_ +             |  R1      
9v              |
- -             ∏ L2
|               |  2R
|_______________|

Are you sure you reproduced the question accurately? It's weird to have those inductors in there, without for example a switch that closes at time t=0 or something along those lines. Also, is the 300 mA the current at some specific time, or after a long time has passed?

Also, did you mean to say 2R or R2 in the figure?

drkidd22 said:
300ma = 9/R
Total Resistance = 30Ohms

30/2 = 15ohms each resistor?
If R were 300 ohms, then the current would be 9/300≠0.3A.
 
Last edited:
Redbelly98 said:
If R were 300 ohms, then the current would be 9/300≠0.3A.


I mean 30 Ohms, the O makes it look like a 300
 

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