Question

The charge that passes a cross-sectional area A=10-4 m2 varies with time according

to the relation
Q=4 + 2t + t2, where Q is in coulombs and t is in seconds. (a) Find the relation
that gives the instantaneous current at time t =2 s is​

Answer 1

Current = dQ/dt

or I = dQ/dt

Where I represents current.

Which is the rate of flow of charge.

Q=4 + 2t + t²

dQ/dt = 2 + 2t --- This is the relation that gives the instantaneous current.

At time t=2sec

dQ/dt = I = 2 + 2t

= 2 + 2(2)

=2 + 4

= 6A.