f(t) is the charge in coulumbs passing a certain cross section...?

Question

along a wire. find a. the total charge passing the cross section b.the time at which exactl 1c has passed c.the current at t=5s, d.the current at t=8s

f(t)= 10e^(-t/4), 0<(less than or equal to)t<8
0.667(10-t), 8<(less than or equal to)t<10
0, t>(greater than or equal to)10
0, t<0

what about the first question. i just integrated 10e^(-t/4) from 0 to 8
and .677(10-t) from 8 to 10 then add them right???

where did you get 3secs from?? and1 for i? i thought i is in ampere since it's the current. the problem gave 1 coulomb which is q right?

Answer 1

use the equation i=dq/dt

dq=? dt = 3sec i=1
hence charge passed 3 columb