The current strength in an iron conductor with a length of 150 mm and a cross-sectional area of zero

The current strength in an iron conductor with a length of 150 mm and a cross-sectional area of zero as much as two hundred square millimeters is equal to 250 mA what is the voltage at the ends of the conductor.

Given:

l = 150 millimeters = 0.15 meters – the length of the iron conductor;

s = 0.02 square millimeters – cross-sectional area of the iron conductor;

r = 0.098 Ohm * mm2 / m is the specific resistance of the iron conductor;

I = 250 mA = 0.25 Ampere – current in the conductor.

It is required to determine U (Volt) – the voltage at the ends of the conductor.

Find the total resistance of the iron conductor:

R = r * l / s = 0.098 * 0.15 / 0.02 = 0.0147 / 0.02 = 0.735 Ohm.

Then the voltage will be equal to:

U = I * R = 0.25 * 0.735 = 0.18 Volts.

Answer: the voltage is 0.18 volts.