The spiral of the electric iron is made of chromel thread 2.5 m long and 0.2 mm2 in cross section

| February 11, 2021 | education

The spiral of the electric iron is made of chromel thread 2.5 m long and 0.2 mm2 in cross section. What is the power equal to if it is designed for a voltage of 220 V?

The power of the electric iron is calculated by the formula:
P = (U ^ 2) / R, where U is the voltage in the network (U = 220 V), R is the resistance of the chromel thread.
R = (ρ * l) / S, where ρ is the resistivity of the chromel thread (ρ = 1.4 * 10 ^ -6 Ohm * m),
l is the length of the chromel thread (l = 2.5 m), S is the cross-sectional area of the chromel thread (S = 0.2 mm ^ 2 = 0.2 * 10 ^ -6 m ^ 2).
Let’s calculate the power of the electric iron:
P = (U ^ 2) / R = (U ^ 2) / ((ρ * l) / S) = (220 ^ 2) / ((1.4 * 10 ^ -6) * 2.5 / (0 , 2 * 10 ^ -6)) = 2766 W.
Answer: The power of the electric iron is 2766 W.



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