Answer:
0.0979 N/c
Explanation:
Electric field, E is given as a product of resistivity and current density
E=jP where P is resistivity and j is current density
But the current density is given as
[tex]j=\frac {I}{A}[/tex] where I is current and A is area and [tex]A=\pi r^{2}[/tex]
Substituting this into the first equation then [tex]E=P\times \frac {I}{\pi r^{2}}[/tex]
Given diameter of 0.259 cm= 0.00259 m and the radius will be half of it which is 0.001295 m
[tex]E=1.72\times 10^{-8}\times \frac {30}{\pi \times 0.001295^{2}}=9.79\times 10^{-2} N/c=0.0979 N/c[/tex]
