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I,m confused

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dirtyboy161

New Member
Pop Quiz:

Three resistors are connected to a source of 240 volts.
The first resistor passes a current of 240 mA. The second has a voltage drop of 110 volts and the third one has a resistance of 208 ohms.

Find: 1) V1=
2) R1=
3) R2=
4) I2=
5) V3=
f) RT=

Can anyone figure this out and explain how to? Thanks.
 

colin55

Well-Known Member
This is a very simple problem.
Firstly, you are told the current through one of the resistors in series is 240mA. This is the current though all the resistors because they are in series. By Ohms law, the total resistance will be 240/.240 = 1,000 ohms.

The third resistor is 208 ohms and the current flowing though it is .24A This means the voltage across it is .24 x 208 = 50v
The voltage across the first resistor is 240 - 110 - 50 = 80v
The resistance of R1 = 333R
The resistance of the second resistor = 1,000 - 208 - 333 = 459R
 
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BrownOut

Banned
You can post on here in the middle of a pop quiz??? Is there a drawing of the circuit? It seems by the question that the 3 resistors are connected in series. If so, use the fact that the current will be the same in all 3, and the problem is easily solved.
 

dirtyboy161

New Member
still confused

Collin 55

I think you have the no.s confused the third resistor has 208 ohms which changes all your numbers. But even with what you gave me
I still am having problems filling in the blanks. I am not very good at this as you can tell. Any further help would be greatly appreciated.

Thank You
 

microtexan

New Member
Man, you're going to have a really rough time in this class!!:eek:
 

xtrmi

New Member
Lol. This is so funny. I don't know how many people in my classes are just interested in passing the class and that is it. Its crazy if you think about it. Just plain crazy.
 

BrownOut

Banned
Collin 55

I think you have the no.s confused the third resistor has 208 ohms which changes all your numbers. But even with what you gave me
I still am having problems filling in the blanks. I am not very good at this as you can tell. Any further help would be greatly appreciated.

Thank You
Do you know Ohm's law? Do yourself a favor, draw out the circuit with the 3 resistors in series. If you don't know what series is, then ask. The circuit must be series, because I don't think it is solvable otherwise. Once you have the circuit drawn, then draw an arrow over each resistor, and write 240mA over each arrow, to remind yourself that the current is the same for each resistor. Now, you should know that all the sereis resistors added together is the total resistance for the circuit. Also, you can calculate the resistance for the one who's voltage drop you are given, because you have the voltage and current, so use Ohm's law to get the resistance. Now you have the values of two of the three resistors, and you know the total resistance ( hint: it was given in an earlier post ) It's a simple addition to find the value of the remaining resistor ie R1 + R2 + R3 = total resistance.

That's just about all I can do without doing it for you.
 

MikeMl

Well-Known Member
Most Helpful Member

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dirtyboy161

New Member
Believe me i am having a rough time in class math is not my strong suit and i'm not sure what this has to do with going to school for a pipe fitter but this is the question they gave me.
 
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