Question

A wire with a length of 150 m and a radius of 0.15 mm carries a current with a uniform current density of 2.8 x 10^7A/m^2. The current is: A) 2.0 A B) 0.63 A C) 5.9A D) 300 A E) 26000 A

Answer 1

The current is 2.0 A.

(A) is correct option.

Step-by-step explanation:

Given that,

Length = 150 m

Radius = 0.15 mm

Current density
`J=2.8*10^(7)\ A/m^2`

We need to calculate the current

Using formula of current density

`J = (I)/(A)`

`I=J*A`

Where, J = current density

A = area

I = current

Put the value into the formula

`I=2.8*10^(7)*\pi*(0.15*10^(-3))^2`

`I=1.97=2.0\ A`

Hence, The current is 2.0 A.