Potential Difference between two points of a circuit

In summary, using Kirchoff's Law and Ohm's Law, the current in the circuit is calculated to be 0.29 Amps. The potential difference between points a and b is found to be 11.95 V.
  • #1
lylos
79
0

Homework Statement


Given the following circuit, what is Vab? Explain...

circuit.jpg



Homework Equations


Kirchoff's Law and Ohm's Law


The Attempt at a Solution



Here is my solution... Is this describing it correctly?

Kirchoff’s Loop Law to find current:
-10 Ω (I) + 30 Ω V – 100 Ω (I) – 5 Ω (I) + 15 V – 40 Ω (I) = 0
45 V = 155 Ω (I)
I = 45 V / 155 Ω or .29 Amps

Potential Difference between points a and b:
1. At point a, we will assume there to be zero potential.
2. By going over the 5 Ω resistor, we lose 1.45 V (5 Ω * .29 A), thus leaving us at - 1.45 V.
3. The 15 V power supply adds 15 V, leaving us with 13.55 V.
4. The 40 Ω resistor takes away another 11.6 V (40 Ω * .29 A), leaving us with 1.95 V.
5. The 5 Ω resistor that we come in contact with next doesn’t take anything away as it doesn’t have current running through it, so we’re left with 1.95 V.
6. Now, we add another 10 V to the potential difference between the point a and point b due to the power supply.
7. We now have a combined Potential Difference between point a and point b to be 11.95 V.
 
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  • #2
I didnt check your math but the rest seems good to me.
 
  • #3


Yes, your solution is described correctly. You have used Kirchoff's Loop Law and Ohm's Law to calculate the current in the circuit and then used the potential differences across each component to determine the potential difference between points a and b. Your explanation is clear and well thought out. Good job!
 

What is potential difference?

Potential difference, also known as voltage, is the difference in electrical potential energy between two points in a circuit. This difference is what causes electric current to flow through the circuit.

How is potential difference measured?

Potential difference is measured in volts (V) using a voltmeter. It is important to connect the voltmeter in parallel to the two points in the circuit between which the potential difference is to be measured.

How does potential difference affect current flow?

Potential difference is directly proportional to current flow, meaning that an increase in potential difference will result in an increase in current flow. This relationship is described by Ohm's Law, which states that current (I) is equal to potential difference (V) divided by resistance (R), or I = V/R.

What factors affect potential difference?

Potential difference is affected by the source of electrical energy, such as a battery or power supply, as well as the resistance in the circuit. Changes in either of these factors can result in a change in potential difference.

Why is potential difference important in a circuit?

Potential difference is essential for the functioning of a circuit. It is what drives the flow of electric current and allows devices to receive the necessary energy to operate. Additionally, potential difference is used in calculations to determine the power and energy consumption of a circuit.

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