Adding a wrench to a series circuit ?

In summary, the addition of the wrench creates a parallel circuit with the wrench being in parallel with R2. The voltage across R2 is 6 V and the voltage across R1 is 24 V. The current through R1 is 6 A and the current through the wrench is 5 A, following Kirchhoff's current law. The effective resistance of two resistors in parallel is less than the resistance of either one.
  • #1
mirandab17
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0
If someone could also clarify how to go about this one.

Does the wrench added make it a parallel circuit?
I found the voltage of the initial circuit by simply doing V = IR = (3)(10) = 30 V.

The current flowing through the 4 ohm resistor must be the same as before... so the current for that is still 3.0 A?

Help please :s
 

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  • #2
mirandab17 said:
If someone could also clarify how to go about this one.

Does the wrench added make it a parallel circuit?
I found the voltage of the initial circuit by simply doing V = IR = (3)(10) = 30 V.

The current flowing through the 4 ohm resistor must be the same as before... so the current for that is still 3.0 A?

Help please :s
attachment.php?attachmentid=44481&d=1330405295.png


Well, in a sense the wrench makes it a parallel circuit, with the wrench being in parallel with R2. But the resistance of the wrench is small. (I assume that it's much smaller than the resistance of either resistor.) The effective resistance of two resistors in parallel is less than the resistance of either one.
 
  • #3
mirandab17 said:
If someone could also clarify how to go about this one.

Does the wrench added make it a parallel circuit?
the wrench is parallel with R2.
mirandab17 said:
I found the voltage of the initial circuit by simply doing V = IR = (3)(10) = 30 V.

Correct, for the emf of the battery.

mirandab17 said:
The current flowing through the 4 ohm resistor must be the same as before... so the current for that is still 3.0 A?

NO! It is the emf that is the same as before, 30 V. The currents will change. What is the voltage across R2 if 1 A current flows through it? What is then the voltage across R1? And what current flows through it? And then apply Kirchhoff's current Law.
 
  • #4
I don't know how to go about finding the current through the wrench though... especially if it has negligible resistance.
 
  • #5
oooh okay let me do that then...
 
  • #6
Voltage across R2
V = IR = (1)(6) = 6 V

Is the voltage across R1 the EMF minus the voltage parallel?
So voltage across R1 = 30 - 6 = 24 V?
Current through R1 would be I=V/R = 24/4 = 6 A.

Oh! And then if there's only 1 A through R2 then there must be 5 A through the wrench due to Kirchoff's current law...
 
  • #7
mirandab17 said:
Voltage across R2
V = IR = (1)(6) = 6 V

Is the voltage across R1 the EMF minus the voltage parallel?
So voltage across R1 = 30 - 6 = 24 V?
Current through R1 would be I=V/R = 24/4 = 6 A.

Oh! And then if there's only 1 A through R2 then there must be 5 A through the wrench due to Kirchoff's current law...

Excellent!:smile:

ehild
 
  • #8
Thanks! Finally get it, awesome.
 

What is a series circuit?

A series circuit is a type of electrical circuit in which the components are connected in a single loop, with the current flowing through each component one after the other. This means that if one component fails, the entire circuit will be interrupted.

Why would you add a wrench to a series circuit?

A wrench can be used as a variable resistor in a series circuit, allowing you to control the amount of current flowing through the circuit. This can be useful for testing the behavior of different components or for adjusting the overall resistance of the circuit.

What effect does adding a wrench have on a series circuit?

Adding a wrench to a series circuit will increase the overall resistance of the circuit, which will decrease the amount of current flowing through it. This can also cause a decrease in the voltage across each component in the circuit.

Can any type of wrench be used in a series circuit?

Ideally, a variable resistor or rheostat wrench should be used in a series circuit, as these are designed specifically for controlling the flow of electrical current. However, in a pinch, any wrench with a metal body and insulated handle could potentially be used.

Are there any risks associated with adding a wrench to a series circuit?

Yes, there are some risks associated with adding a wrench to a series circuit. If the wrench is not properly insulated, it could cause a short circuit or electrical shock. It is important to use caution and ensure that the circuit is properly grounded before adding a wrench.

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