25. Coulomb's law says F12 = k 72 , Where k = =. Start from the Coulomb's law and use the right figure, prove the Gauss's law for point charge q: HE . dA = 9. Fig. 3 26. A cylindrical conductor with radius R carries a current i. The current is uniformly distributed over the cross-sectional area of the conductor. Find the magnetic field as a function of the distance r from the conductor axis for points inside (r