Resistivity question help

[Tea cup]

The question is : Copper wire, with a diameter of 1.5mm, must be of such a length as to give a resistance of 0.6 ohms. calculate the length of this wire. Take the resistivity of copper as 0.017 microhm metres.

 

[Harald Kapp]

resistance = resistivity / cross sectional area * length
reverse this equation to get the length from a given resistance.

 

[WHONOES]

If I remember correctly, the 0.017μΩ meters refers to a 1 Metre cube of solid copper. Calculate from there.

 

[Harald Kapp]

If I remember correctly, the 0.017μΩ meters refers to a 1 Metre cube of solid copper.

That would be valid for a cube of any size...

 

[WHONOES]

No, I think it refers to the actual resistance of the said 1 Metre cube.

 

[Tea cup]

Thank you for your help

 

[Ratch]

No, I think it refers to the actual resistance of the said 1 Metre cube.

Resistivity is an intrinsic property of a material and does not depend on the resistance value of any size or shape. In other words, a cubic foot has the same resistivity as a cubic meter of the same material.

Ratch

 

[Ratch]

The question is : Copper wire, with a diameter of 1.5mm, must be of such a length as to give a resistance of 0.6 ohms. calculate the length of this wire. Take the resistivity of copper as 0.017 microhm metres.

Calculations are straight forward. Keep the units consistent.


Ratch

 

[The Electrician]

No, I think it refers to the actual resistance of the said 1 Metre cube.

If by the phrase "resistance of the said 1 Metre cube", you mean the resistance measured between two of the plane surfaces of the cube which are on opposite sides of the cube with a perfect conductor used to make the connection to each face, you should be aware that the resistance will be the same for any size cube.