Answer to Question #283378 in Electricity and Magnetism for Qwerty

Question

if the conduction current density J=5sin(wt-20z)ay +cos(wt-20z)az mA/m^2 then evaluate the volume charge density

Answer 1

$\rho=\dot J=\text {grad} J=5\omega\cos(\omega t-20z)a_y-\omega \sin(\omega t-20z)a_z.$