Question

current density in the wire if an electric field E is passing through it. Write this in terms of the resistivity and the other variables in the problem.

Answer 1

Complete Question

The complete question is shown on the first and second uploaded image

Note : The resistance is R = 147 Ohms

Answer:

The current density in terms of resistivity is  $J = \frac{E}{\rho}$

The current is  $I = 176 *10^{-3} \ A$  

Explanation:

From the question we are told that

   The length of the wire is  $L = 2.75 \ m$

    The radius of the circular cross-sectional  area  is  $r = 1.76 \ mm = 0.00176 m$

    The electric field strength is E =9.41  V/m

 Generally the current density is mathematically represented as

      $J = \frac{E}{\rho}$

Here $\rho$ is the resistivity of the wire which is mathematically represented as

       $\rho = \frac{R * A}{L}$

So

      $J = \frac{EL }{RA}$

Here A is the cross-sectional  area  which is mathematically represented as

     $A =\pi r^2$

So  

      $J = \frac{EL }{R * \pi r^2 }$

Generally the current density can also be mathematically represented as

       $J = \frac{I}{A}$

So

      $\frac{EL }{RA} = \frac{I}{A}$

=>   $I = \frac{EL}{R}$

=>  $I = \frac{9.41 2.75}{147 }$  

=>  $I = 176 *10^{-3} \ A$