In the coil of an electric heater made of nickelin wire with a cross-sectional area of 0.1 mm², at a voltage of 220 V

In the coil of an electric heater made of nickelin wire with a cross-sectional area of 0.1 mm², at a voltage of 220 V, the current is 4 A. What is the length of the wire that makes up the coil?

Given:

S = 0.1 mm²;

U = 220 V;

I = 4 A;

p = 0.4 (Ohm * mm²) / m – resistivity of nickel.

To find:

l -?

Decision:

To find the length of the wire, we use the formula: R = (p * l) / S hence l = (R * S) / p;

R = U / I = 220/4 = 55 Ohm;

l = (55 * 0.1) / 0.4 = 13.75 m

Answer: Wire length 13.75 m.