Trouble finding the current through this resistor in the circuit

In summary, the conversation discusses how to use the substitution method to solve a system of equations. The speaker is confused about how to use the substitution ##I_3 = I_1-I_2## to get the equations in terms of ##I_1## and ##I_2##. They ask for someone to demonstrate the process and show their work for any potentially difficult steps.
  • #1
guyvsdcsniper
264
37
Homework Statement
FIind the current through and the potential difference across the 100 ohm resistor.
Relevant Equations
junction rule. loop rule
I was following this problem up until they say we can they state I3= I1-I2. I understand why we can say that but I don't see how I can use that to get the system of equation in terms of I1 and I2 at the bottom. Could someone show me how this was done?
Screen Shot 2021-10-28 at 11.13.56 AM.png
 
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  • #2
You have the two equations

1635443429139.png

Take the first of these two equations and substitute ##I_3 = I_1-I_2##. This means to replace ##I_3## in the equation by the quantity ##(I_1-I_2)##. Then simplify.

Do the same for the second equation.

Show your work so we can help with any particular step for which you have trouble.
 
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Likes guyvsdcsniper, Steve4Physics, DaveE and 1 other person

FAQ: Trouble finding the current through this resistor in the circuit

What is the purpose of finding the current through a resistor in a circuit?

The current through a resistor is important because it allows us to calculate the voltage drop across the resistor, which is necessary for understanding the behavior of the circuit.

Why is it sometimes difficult to find the current through a resistor in a circuit?

There are a few reasons why it may be difficult to find the current through a resistor in a circuit. One reason is that there may be multiple resistors in the circuit, making it more complex to calculate the current. Another reason is that the circuit may have other components, such as capacitors or inductors, that affect the flow of current.

How can I find the current through a resistor in a circuit?

To find the current through a resistor in a circuit, you can use Ohm's Law, which states that current (I) is equal to voltage (V) divided by resistance (R). So, I = V/R. Alternatively, you can use Kirchhoff's Current Law, which states that the sum of all currents entering and exiting a node in a circuit is equal to zero.

What factors can affect the current through a resistor in a circuit?

The current through a resistor in a circuit can be affected by a few different factors. These include the voltage of the power source, the resistance of the resistor, and the presence of other components in the circuit that may affect the flow of current.

What are some common techniques for measuring the current through a resistor in a circuit?

There are a few common techniques for measuring the current through a resistor in a circuit. One method is to use a multimeter, which can measure the voltage drop across the resistor and calculate the current using Ohm's Law. Another method is to use a current probe, which can measure the current directly without interrupting the circuit. Additionally, some circuits may have built-in current sensing components that can provide an accurate measurement of the current through a resistor.

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