To make a 3 ohm resistance, the material is manganese copper wire with a cross-sectional area of 0.21 cubic mm. How long is the manganese copper wire?

To make a 3 ohm resistance, the material is manganese copper wire with a cross-sectional area of 0.21 cubic mm. How long is the manganese copper wire?

First, the resistivity of manganin is 4.4 * 10 ^ (- 7) ohmm2
Then 0.00000044 * L / S = 3
S = 0.21 sq mm = 0.00000021 sq m
1 / 4.4 = 1.43M

Bv-2.5 copper conductor resistance

Calculation formula of conductor resistance
Resistance R = ρ (L / s)
R = resistance in ohm
ρ = resistivity (copper resistivity = 0.017, aluminum resistivity = 0.029)
L = length of line in meters
S = section of the line in square millimeters

The resistance of copper wire is urgent,

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There is a 1000 turn coil, the magnetic flux passing through it increases from 0.02wb to 0.09wb in 0.4s, and the induced electromotive force in the coil is calculated. If the resistance of the coil is 10 ohm, when a 990 ohm electric heater is connected in series to form a closed circuit, what is the current passing through the electric heater?

Induced electromotive force E = 1000 x (0.09-0.02) / 0.4 = 175 (V); current I = E / (10 + 990) = 175 / 1000 = 0.17 (a)