Engineering

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'.

1 Answer

  • Answer:

    1 x 10⁻¹¹m²

    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

NEWS TODAY