The heating element of an electric iron U = 220V consists of a nichrome wire 8 m

| May 16, 2021 | education

The heating element of an electric iron U = 220V consists of a nichrome wire 8 m long and 0.3 mm in diameter. Determine the power of the iron

U = 220 V.

L = 8 m.

d = 0.3 mm = 3 * 10 ^ -4 m.

ρ = 1.1 * 10 ^ -6 Ohm * m.

N -?

The power N of the heating element of the iron is expressed by the formula: N = U ^ 2 / R, where U is the voltage to which the iron is connected, R is the resistance of the heating element of the iron.

Since the heating element in it is a nichrome wire with a length L and a cross-sectional diameter d, its resistance R is expressed by the formula: R = ρ * L / S.

S = P * d ^ 2/2.

R = 2 * ρ * L / P * d ^ 2.

The formula for determining the power of the iron will take the form: N = P * d ^ 2 * U ^ 2/2 * ρ * L.

N = 3.14 * (3 * 10-4 m) ^ 2 * (220 V) ^ 2/2 * 1.1 * 10 ^ -6 Ohm * m * 8 m = 777 W.

Answer: the power of the iron is N = 777 W.



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