The quantity of charge q (in coulombs) that has passed through a surface of area 1.92 cm2 varies with time according to the equation q = 4t3 + 5t + 6, where t is in seconds.
(a) What is the instantaneous current through the surface at t = 1.02 s?
A
(b) What is the value of the current density?
kA/m2