Cutting a Copper Wire for Different Resistances

In summary, the conversation is about a Physics homework problem involving a copper wire with a resistance of 10.0 Ohm. The question is about finding the point along the wire where it must be cut so that one piece has a resistance that is 4.0 times the other piece. After some calculations, the answer is determined to be R=2 Ohm and 4R=8 Ohm. The equation for resistivity, R= rho*L/A, is used and the concept of L1 + L2 = Ltotal is discussed as a way to solve the problem. The person is having trouble with using this concept and is asking for help.
  • #1
DevilishNole
3
0
I need help with one of my Physics homework problems please!

A certain copper wire has a resistance of 10.0 Ohm. At what point along its length must the wire be cut so that the resistance of one piece is 4.0 times the resistance of the other? What is the resistance of each piece?

I worked it out and got that R=2 Ohm, and so the other piece, 4R, has to be equal to 8 Ohm. I used the equation for resistivity, R= rho*L/A using 4R in the place of R and solved for L. I replaced this back into the original equation but end up in a loop, with R=2. I have no idea what I'm doing wrong; can anyone please help?!
 
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  • #2
You need to use the fact that L1 + L2 = Ltotal.
 
  • #3
I did that on my second attempt to the problem but to no avail because I do not know when to use the "L1+L2" equation and the "Ltotal"
 
  • #4
Consider it as a proportion.
 

1. What is resistance?

Resistance is the measure of how difficult it is for an electrical current to flow through a material. It is measured in ohms (Ω) and is dependent on the material's properties, length, and cross-sectional area.

2. How does resistance affect cut wires?

Cutting a wire can increase its resistance because it reduces the cross-sectional area of the wire, making it more difficult for the current to flow through. It can also introduce imperfections in the wire, such as sharp edges or gaps, which can increase resistance.

3. What factors can affect the resistance of cut wires?

The resistance of cut wires can be affected by the material of the wire, its length, cross-sectional area, and temperature. It can also be influenced by the type of cut, as well as any impurities or imperfections in the wire.

4. How can resistance of cut wires be measured?

The resistance of cut wires can be measured using a multimeter, which can give an accurate reading of the resistance in ohms. The wire can also be connected to a power source and the resulting current and voltage can be used to calculate the resistance using Ohm's law (R=V/I).

5. Can the resistance of cut wires be reduced?

The resistance of cut wires can be reduced by using thicker wires with a larger cross-sectional area, as well as minimizing any imperfections in the wire. Additionally, using materials with lower resistivity, such as copper, can also help reduce the resistance of cut wires.

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