The iron wire has some dimensions and a resistance of 100 ohms. what will be the resistance of an iron wire

| September 6, 2021 | education

The iron wire has some dimensions and a resistance of 100 ohms. what will be the resistance of an iron wire, the length of which is 2 times less, and the cross-sectional area is 2 times more?

R1 = 100 ohms.

L2 = L1 / 2.

S2 = 2 * S1.

R2 -?

The electric current resistance R of a homogeneous conductor is determined by the formula: R = ρ * L / S, where ρ is the resistivity of the material from which the conductor is made, L is the length of the conductor, S is its cross-sectional area.

Let us express the initial resistance of the wire by the formula: R1 = ρ * L1 / S1.

ρ = R1 * S1 / L1.

Let us express the second wire: R2 = R1 * S1 * L2 / S2 * L1 = R1 * S1 * L1 / 2 * 2 * S1 * L1 = R1 / 4.

R2 = 100 Ohm / 4 = 25 Ohm.

Answer: the resistance of the iron will become R2 = 25 ohms.



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