Please show all work and specify the correct answer at the b
Please show all work and specify the correct answer at the bottom. Please do not put down an answer that is not one of the choices, I will thumbs you down. Correct answer will get five stars and thumbs up.
The cross section of a long coaxial cable is shown in the figure, with radii as given. The linear charge density on the inner conductor is -20 nC/m and the linear charge density on the outer conductor is -70nC/m. The inner and outer cylindrical surfaces are respectively denoted by A, B, C, and D, as shown. ( 0 = 8.85 × 10-12 C2/N · m2) The radial component of the electric field at a point that 38 mm from the axis is closest to
| -9500 N/C. | |
| +9500 N/C. | |
| -3.3×104 N/C. | |
| +3.3×104 N/C. | |
| zero |
Solution
Exploiting cylindrical symmetry and using a cylindrical gaussain surface with radius r1 = 38 mm
E = - 2 k inner / r
= (-2 * 9 * 109 * -20 * 10-9) / (0.038 m)
= 9500 N/C
