# Resistance of a composite conducting wire

• Linus Pauling
In summary, the conversation discusses the calculation of resistance for a composite wire made of copper and iron. The wire is 80 cm long, with a diameter of 5.50 mm and is made by welding a 20-cm-long copper wire and a 60-cm-long iron wire together. The equation used for resistance is R = pL/A, where p is resistivity, L is length, and A is cross-sectional area. The calculation involves finding the resistances for each metal separately and then adding them together, resulting in a total resistance of 0.0104 ohm or 10.4 milliohm. There is a discussion about the value of r, with one person asking if it is equal to d

#### Linus Pauling

1. An 80-cm-long wire is made by welding a 5.50 mm-diameter, 20-cm-long copper wire to a 5.50 mm-diameter, 60-cm-long iron wire. What is the resistance of the composite wire?
2. p = resistivity, R = pL/A 3. r = 0.001375 m goes into A = pi*r2. I used the above equation for R separately for the length of the wire for each metal, then added them together. I figured they would just add linearly like resistors in series.

My calculation came out to be 9.80*10-3 ohm + 5.72*10-4ohm = 0.0104 ohm = 10.4 milliohm

Isn't r equal to d/2 ?

The method you described is OK, but I couldn't get the same result. Could you give
a more detailed calculation?

## 1. What is a composite conducting wire?

A composite conducting wire is a wire that is made up of multiple materials, typically a metal and a non-metal, to combine their properties and create a wire with specific characteristics.

## 2. How does the resistance of a composite conducting wire compare to a single material wire?

The resistance of a composite conducting wire is typically lower than that of a single material wire, as the combination of materials allows for better conductivity.

## 3. What factors affect the resistance of a composite conducting wire?

The resistance of a composite conducting wire is affected by the types of materials used, their proportions, and the length and thickness of the wire.

## 4. Can the resistance of a composite conducting wire be calculated?

Yes, the resistance of a composite conducting wire can be calculated using the formula R = ρL/A, where R is resistance, ρ is the resistivity of the materials, L is the length of the wire, and A is the cross-sectional area.

## 5. What are some common applications of composite conducting wires?

Composite conducting wires are commonly used in electronics, telecommunications, and power transmission due to their improved conductivity and strength compared to single material wires.