Question

calculate the resistance of the meterial of wire 1 m long,0.4 mm diameter and having a resistance of 2 ohm ?​

Answer 1

Hi,

Here is your answer

Given:

Length of wire(l)=1m

Diameter of wire(d)=0.4mm=0.0004m

Hence radius(r)=d/2=0.0002m

Resistance(R)=2Ω

To Find:

Resistivity(ρ)

Solution

The equation for finding resistivity is given as

ρ=RA/l

Area of cross section of conductor =πr²

Area(A)=3.14×(0.0002)²

Area=1.256×10⁻⁷m²

Substitute the given datas in the equation for finding resistivity

We get

ρ=2×1.256×10⁻⁷/1

ρ=2.512×10⁻⁷Ωm

Notes:

1. Resistivity does not depend on area and length of conductor

2. The unit of resistivity is ohm-metre(Ωm)

3. Remember to convert all the given datas to their SI units before calculating.

Hope this helps you.