If a current of 2.4 A is flowing in a cylindrical wire of diameter 2.0 mm, what is the average current density in this wire? A) 7.6 × 10⁵ A/m² B) 5.2 × 10^-6A/m² C) 1.9 × 10⁵ A/m² D) 3.6 × 10⁵ A/m² E) 21 × 10^-6 A/m²

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Quizplus · Accepted Answer

Current density is given by J = I/A, where I is the current and A is the cross-sectional area of the wire. The cross-sectional area of a cylindrical wire is given by A = πr^2, where r is the radius of the wire. In this case, the diameter of the wire is 2.0 mm, so the radius is 1.0 mm or 0.001 m. Therefore, the cross-sectional area is A = π(0.001 m)^2 = 3.14 × 10^-6 m^2. The current is 2.4 A, so the current density is J = 2.4 A / 3.14 × 10^-6 m^2 = 7.6 × 10^5 A/m^2.

If a Current of 2