Question

A uniform straight conductor of radius 0.25mm carries a steady current 2A.Calculate the current density

Answer 1

Explanation:

Current density = I / A

Find A

$\pi \: {r}^{2} = 3.14 \times (\frac{1}{4 } \times {10}^{ - 3} ) {}^{2} = 1.96 \times {10}^{ - 7} {m}^{2}$

So current density

$j = \frac{2}{1.96 \times {10}^{ - 7} } \approx \: 1.01 \times {10}^{7} \: \frac{amp}{ {m}^{2} }$