The current in the kettle’s heating element is 4 amperes at 220 volts. Find the resistance of the element

The current in the kettle’s heating element is 4 amperes at 220 volts. Find the resistance of the element and the specific resistance of the metal from which the winding is made, if 18m of wire with a cross section of 0.24mm2 went to make the heater.

I = 4 A.

U = 220 V.

L = 18 m.

S = 0.24 mm2.

R -?

ρ -?

Ohm’s law for a section of a circuit: I = U / R, where I is the current in the circuit, U is the voltage at the ends of the heater wire, R is the resistance of the heater winding.

R = U / I.

R = 220 V / 4 A = 55 Ohm.

To determine the resistance R of a homogeneous cylindrical conductor, we use the formula: R = ρ * L / S, where ρ is the resistivity of the winding material, L is the length of the winding wire, S is the cross-sectional area of the wire.

ρ = R * S / L.

ρ = 55 Ohm * 0.24 mm2 / 18 m = 0.73 Ohm * mm2 / m.

Answer: R = 55 Ohm, ρ = 0.73 Ohm * mm2 / m.