Question

Determine the resistance of 150m of single copper cable whose CSA is 10mm². Take

the resistivity of copper to be 17.2 x 10° ohm/metre'.

Answer 1

1 x 10⁻¹¹m²

Step-by-step explanation:

Given parameters:

Resistivity = 100 x 10⁻⁶Ohm.m

Cross-section = 1mm²

Resistance = 10ohm

Unknown:

length of the nichrome wire = ?

Solution:

To find the length of the nichrome wire, we use the expression below:

L = \frac{RA}{P}PRA

where l is the length of the wire

R is the resistance of the wire

A is the area

p is the resistivity

Now we need to convert area from mm to m;

1000mm = 1 m

1mm² = 1 x \frac{1m}{1000mm} x \frac{1m}{1000mm}1000mm1mx1000mm1m = 1 x 10⁻⁶m²

Input the values in the formula;

L = \frac{100 x 10^{-6} x 1 x 10^{-6} }{10}10100x10−6x1x10−6 = 1 x 10⁻¹¹m²