Question

A copper conductor of area of cross section 40 mm square on a side carries a constant current of 3.2 ×10^-8A.then the current density is(in amp/m^2)
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Answer 1

Explanation:

what is the resistivity

Answer 2

Given:

Area of cross section = 40 mm²

Current = 3.2 × 10⁻⁸ A

To find:

Current density(amp/m²)

Solution:

Copper conductor has cross sectional area = 40 mm²

Current flowing through them = 3.2 × 10⁻⁸ A

First define current density, Current density is defined as the total amount of current flowing through 1 unit of cross sectional area.

Formula used to find current density is-

          $J = \frac{I}{A}$

here, J = current density

        I = current = 3.2 × 10⁻⁸ A

         A = area of cross section = 40mm² = 40 × 10⁻⁶ m²

by putting all the values, current density will be-

            $J = \frac{3.2 \times 10^-^8 A}{40 \times 10^-^6 m^2}$

            $J = \frac{3.2}{40} \times 10^-^2 Am^-^2$

            J = 0.08 × 10⁻² Am⁻²

Therefore, current density is 0.08 × 10⁻² Am⁻².