Potential difference between two points (VA - VB)

In summary, the conversation discusses solving for the voltage difference between points VA and VB in a circuit with a closed switch. The solution involves using the junction rule and loop rule to find the currents in the circuit, and then using those currents to calculate the voltage difference. One person in the conversation is unsure if their calculation is correct and is seeking confirmation.
  • #1
johnknee
15
0

Homework Statement


Q. With the switch closed, what is the voltage difference, VA-VB ?

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Homework Equations


Junction rule: I3 = I1 + I2
Loop rule(s)

The Attempt at a Solution


I solved for the currents in this circuit when the switch is closed.

Top loop(clockwise): +10V1 - 15*I1 - 47*I1 + (0V since I'm assuming no Voltage drop across switch) = 0
Bottom loop(counter clockwise): -5*I2 + 6V2 - 22*I2 + 0V = 0

For the top loop: I isolated I1 and got 10/62 = 0.161 = I1
For the bottom loop: I got 6/27 = 0.222A = I2
I1 + I2 = 0.161 + 0.222 = 0.383A.= I3

for the voltage difference VA - VB, I tried doing this with the guidance of a friend.
Va = 10 - I1*15 = 7.585 V.
Vb = Va - Vc - 6 (Vc being the voltage at node C where I3 flows through.)
Then Vc = Va - i1*47 = 7.585 - (7.567) = 0.018 V.
Vb = Va - Vc - 6 = 7.585 - 0.018 - 6 = 1.567 V.
Finally Va - Vb = 7.585 - 1.567 = 6.018 V

I am not sure whether I did this part correct.
 
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  • #2
You already have a thread dealing with this circuit. You must keep all related questions in that thread.

This thread will be deleted shortly.
 

FAQ: Potential difference between two points (VA - VB)

What is potential difference?

Potential difference, also known as voltage, is the difference in electric potential energy between two points. It is measured in volts (V) and represents the amount of work needed to move a unit of electric charge from one point to another.

What causes potential difference?

Potential difference is caused by the presence of an electric field. This electric field can be created by a variety of sources, such as a battery, generator, or even the natural charge distribution in a material. The direction of the electric field determines the direction of the potential difference.

How is potential difference measured?

Potential difference can be measured using a voltmeter, which is a device that measures the difference in electric potential between two points. The voltmeter is connected in parallel with the two points, and the reading it displays is the potential difference between those points.

What is the unit of measurement for potential difference?

Potential difference is measured in volts (V). A volt is defined as the potential difference between two points where one joule of work is required to move one coulomb of electric charge from one point to the other.

How does potential difference affect the flow of electric current?

Potential difference is directly related to the flow of electric current. A higher potential difference means a greater difference in electric potential energy, which results in a higher rate of flow of electric charge. This relationship is described by Ohm's Law, which states that the current (I) is equal to the potential difference (V) divided by the resistance (R): I = V/R.

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