Three Unknown Resistances: Solving for Unknowns in a System of Equations

  • Thread starter flash
  • Start date
In summary, the conversation discusses finding three unknown resistances using three equations. The speaker suggests using a method that involves taking the least common multiple and rearranging the equations to simplify them. They also mention that it may be easier to solve the equations using this method.
  • #1
flash
68
0
I need to find three unknown resistances given the following three equations:

[tex]
\frac{1}{R_2+R_3} + \frac{1}{R_1} = \frac{1}{670}
[/tex]

[tex]
\frac{1}{R_1+R_3} + \frac{1}{R_2} = \frac{1}{679}
[/tex]

[tex]
\frac{1}{R_1+R_2} + \frac{1}{R_3} = \frac{1}{1349}
[/tex]

I figured since there are three unknowns and three equations it is possible, but I can't see how its done.
 
Physics news on Phys.org
  • #2
Sorry, I'm in a slight hurry, but it may be done in this way,

If you take LCM in all the three equations, you find that the numerator of the LHS becomes equal. If the denominators are take to the RHS, you'll get something like

[tex]\displaystyle \frac{R_1(R_2+R_3)}{670}=\frac{R_2(R_1+R_3)}{679}=\frac{R_3(R_1+R_2)}{1349}[/tex]

The above equation might help as it is much simpler. Maybe you can try solving the above.

Regards,
Sleek
 
  • #3
Wow, thanks heaps. Took me a while to figure out how you got that :) It should be a lot easier now.
 

What is the purpose of finding unknown resistances?

The purpose of finding unknown resistances is to determine the resistance value of a component or circuit. This is important in understanding how electricity flows and how different components affect the overall resistance of a circuit.

How do you find unknown resistances?

One way to find unknown resistances is by using Ohm's Law, which states that resistance is equal to voltage divided by current. By measuring the voltage across a component and the current flowing through it, you can calculate the resistance using this formula.

What tools are needed to find unknown resistances?

To find unknown resistances, you will need a multimeter, which is a device that measures voltage, current, and resistance. You may also need other tools such as a breadboard, wires, and resistors to build a circuit for testing.

What are some common sources of error when finding unknown resistances?

Some common sources of error when finding unknown resistances include using a faulty or inaccurate multimeter, not measuring the voltage and current correctly, and not taking into account any internal resistance in the circuit being tested.

How does finding unknown resistances contribute to scientific research?

Finding unknown resistances is an important part of scientific research as it helps to determine the behavior and properties of different materials and components. This information can then be used to design and improve technologies and devices in various fields such as electronics, engineering, and physics.

Similar threads

  • Introductory Physics Homework Help
Replies
1
Views
218
  • Introductory Physics Homework Help
Replies
23
Views
336
  • Introductory Physics Homework Help
Replies
16
Views
1K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
16
Views
1K
  • Introductory Physics Homework Help
Replies
7
Views
3K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
7
Views
743
  • Introductory Physics Homework Help
Replies
11
Views
674
  • Introductory Physics Homework Help
Replies
3
Views
791
Back
Top