Determine the specific resistance of a conductor with a length of 50 m and a cross-section of 1.2 mm ^ 2

Determine the specific resistance of a conductor with a length of 50 m and a cross-section of 1.2 mm ^ 2, if the consumer’s power is 900 W, and the voltage in the network is 220 V.

Given:

l = 50 meters – conductor length;

s = 1.2 mm2 (square millimeters) is the specific cross-sectional area of ​​the conductor;

W = 900 watts – consumer power;

U = 220 Volts – voltage of the electrical network.

It is required to determine r (Ohm * mm2 / m) – the resistivity of the conductor.

Find the total resistance of the conductor:

R = U / I = U / (W / U) = U ^ 2 / W = 220 ^ 2/900 = 48400/900 = 484/9 = 54 ohms (the result has been rounded to whole).

Then the resistivity will be equal to:

r = R * s / l = 54 * 1.2 / 50 = 64.8 / 50 = 1.3 Ohm * mm2 / m (the result has been rounded to one decimal place).

Answer: the resistivity of the conductor is 1.3 Ohm * mm2 / m.