Question

The quantity of charge flowing through a certain cross section varys with time and is given by Q=3t^2+15t+2.Find the instantaneous current through the surface at time=2 seconds?

Answer 1

Answer:

$i = \frac{dQ}{dt}\\ \\i = \frac{d}{dt}(3t^2+15t+2) = 6t+15$

at time t = 2s

i = 6(2)+15 = 27A