Question

A conductor carries a current of 50 μ A. If the area of cross-section of the conductor is 50 mm², then value of the current density in Am⁻² is
(a) 0.5
(b) 1
(c) 10⁻³
(d) 10⁻⁶

Answer 1

A conductor carries a current of 50 μ A. If the area of cross-section of the conductor is 50 mm², then value of the current density in Am⁻² is

(a) 0.5

(b) 1

(c) 10⁻³

(d) 10⁻⁶

solution : current density is the rate of change of current per unit area of cross section.

i.e., $J=\frac{I}{A}$

where J denotes current density , I denotes current and A is cross sectional area.

here, I = 50μA = 50 × 10^-6 A

and A = 50mm² = 50 × 10^-6 m²

then, J = I/A = 50 × 10^-6 A/50 × 10^-6 m²

= 1 A/m²

hence, option (B) is correct choice.

Answer 2

Answer:

I think soo the answer is 1Am^-2