Resistance of copper wires

In summary, the conversation discusses the resistance of two copper wires with different lengths and cross sectional areas. The formula used to calculate resistance is R = pL/A, where p represents resistivity. The solution involves substituting the new values of length and area into the equation to find the resistance of the second copper wire.
  • #1
zelda1850
66
0

Homework Statement



a copper wire of length of length L and cross sectional area A has resistance R. A second copper wire at the same temperature has a length of 2L and a cross sectional area of 1/2 A. what is the resistance of the second copper wire?

Homework Equations



R = pL/A

L = 2
A = 1/2
p = how do i find p

The Attempt at a Solution



p stand for resistivty but how do i know it in this problem
 
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  • #2


In the relevant equation replace L by 2L and A by A/2 to get new resistance.
 
  • #3


oh should the answer come out to be 1R
 
  • #4


yes.
 
  • #5


zelda1850 said:
oh should the answer come out to be 1R
No.
New resistance R' = ρ*2L/A/2 = ...?
 
  • #6


i think p would be 1.72 x 10 exponent -8 since it is on copper
so i do 1.72x10 exponent -8 * 2 m/ 2 a is that the right equation?
 

1. What is the resistance of copper wires?

The resistance of copper wires depends on various factors such as the length, diameter, and temperature of the wire. However, on average, the resistance of copper wires is around 1.68 x 10^-8 ohms per meter (Ω/m).

2. What is the relationship between the length of the wire and its resistance?

There is a direct relationship between the length of the copper wire and its resistance. As the length of the wire increases, the resistance also increases. This is because the longer the wire, the more difficult it is for the electrons to travel through it, resulting in a higher resistance.

3. How does the diameter of the wire affect its resistance?

The diameter of the copper wire has an inverse relationship with its resistance. As the diameter increases, the resistance decreases. This is because a thicker wire allows more space for the electrons to flow, reducing the chances of collisions and therefore, lowering the resistance.

4. Does temperature affect the resistance of copper wires?

Yes, temperature has a significant impact on the resistance of copper wires. As the temperature increases, the resistance of the wire also increases. This is because higher temperatures cause the atoms in the wire to vibrate more, making it harder for electrons to pass through, resulting in a higher resistance.

5. How can we reduce the resistance of copper wires?

There are a few ways to reduce the resistance of copper wires. One way is to increase the diameter of the wire, as mentioned earlier. Another way is to use materials with lower resistivity, such as silver or gold. Additionally, keeping the wire at a lower temperature can also help reduce its resistance. Lastly, using thicker and shorter wires can also minimize resistance.

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