Current Calculation Problem (Probably Simple)

In summary, the conversation is about a basic circuit problem involving a cell with an e.m.f. of 2V and internal resistance of 1 Ohm. The person is asking for help in calculating the current through A, as well as the current through B and the potential difference between the terminals of the cell. They eventually solve the problem on their own after struggling for hours.
  • #1
Iscariot
7
0
A really basic circuit problem which I just don't understand.

In the attached figure, C is a cell of e.m.f. 2V and internal resistance 1 Ohm. Calculate:

a) the current through A
b) the current through B
c) the p.d. between the terminals of the cell

I really don't understand how to calculate the current through A. If someone could just help me with that then I'd appreciate it, I'm hoping that from someone pointing out what's probably obvious in part A, I'll be able to do B and C by myself.
 

Attachments

  • circuit problem.jpg
    circuit problem.jpg
    7.8 KB · Views: 407
Physics news on Phys.org
  • #2
Never mind, I solved my own question. Sorry about this, it took me hours.
 
Last edited:
  • #3


First of all, it is important to understand the basic principles of electricity in order to solve this problem. In this circuit, the cell (C) acts as a source of electrical energy, providing an electromotive force (e.m.f.) of 2V. However, the cell also has an internal resistance of 1 Ohm, which means that some of the energy is lost as heat within the cell itself.

To calculate the current through A, we can use Ohm's Law, which states that the current (I) flowing through a circuit is equal to the voltage (V) divided by the resistance (R). In this case, the resistance is the sum of the internal resistance of the cell (1 Ohm) and the resistance of the wire connecting A and B. Let's call this resistance R1.

Therefore, the current through A can be calculated as I = V/(R1 + 1 Ohm). We know that the voltage provided by the cell is 2V, so we just need to find the value of R1 in order to solve for the current.

To find the value of R1, we can use Kirchhoff's Voltage Law, which states that the sum of the voltage drops in a closed loop circuit must equal the voltage supplied by the source. In this case, the loop is A-B-C-A, and the voltage drops are V1 (between A and B) and V2 (between B and C).

Since we know that the voltage drop across the cell is 2V, and the voltage drop across the internal resistance is 1V (due to Ohm's Law), we can set up the following equation:

2V = V1 + V2 + 1V

We also know that the voltage drop across a resistor is equal to the current flowing through it multiplied by its resistance (V = IR). Therefore, we can rewrite the equation as:

2V = I*R1 + I*1 Ohm + 1V

Substituting the value of I from our previous equation, we get:

2V = (2V/(R1 + 1 Ohm))*R1 + (2V/(R1 + 1 Ohm))*1 Ohm + 1V

Simplifying and rearranging, we get:

2V = 2V + 2V*R1/(R1 + 1 Ohm)

Solving for R1, we get:

R
 

1. What is a "Current Calculation Problem"?

A Current Calculation Problem is a mathematical problem that involves determining the magnitude and direction of an electric current in a circuit.

2. How do you solve a Current Calculation Problem?

To solve a Current Calculation Problem, you need to use Ohm's law and Kirchhoff's laws to analyze the circuit and determine the values of voltage, resistance, and current in the different components. Then, you can use basic algebraic equations to calculate the current in the circuit.

3. What are some common mistakes when solving a Current Calculation Problem?

Some common mistakes when solving a Current Calculation Problem include forgetting to convert units, using incorrect values for resistance or voltage, and not properly applying Kirchhoff's laws.

4. Can you provide an example of a Current Calculation Problem?

Sure! Let's say we have a circuit with a 12V battery, a 20 ohm resistor, and a 10 ohm resistor in series. To calculate the current in the circuit, we can use the formula I = V/R. So, the total resistance in the circuit is 20 + 10 = 30 ohms. Therefore, the current is 12V/30 ohms = 0.4 amps.

5. Why is it important to be able to solve Current Calculation Problems?

Being able to solve Current Calculation Problems is important for understanding and analyzing electrical circuits, which are essential in many fields such as engineering, physics, and electronics. It also helps in troubleshooting and identifying potential issues in circuits.

Similar threads

  • Introductory Physics Homework Help
Replies
8
Views
860
  • Introductory Physics Homework Help
Replies
4
Views
944
  • Introductory Physics Homework Help
Replies
2
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
205
  • Introductory Physics Homework Help
Replies
3
Views
562
  • Introductory Physics Homework Help
Replies
2
Views
304
  • Introductory Physics Homework Help
Replies
4
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
736
  • Introductory Physics Homework Help
Replies
6
Views
2K
  • Introductory Physics Homework Help
Replies
9
Views
968
Back
Top