Solve the each parts of following problem given below:

Problem: Under certain conditions in certain devices, the behavior of the current in a conductor can be represented as a function of time by the equation I(t) = Ioe^(-t/tau). Here Io is the current at t = 0 and (tau) is known as the time constant. In this case, tau = 8.00 ms and the initial current Io = 4.05 mA.

Part A: Determine the amount of charge passing through a fixed point in the conductor in the time interval t1 = 0 to t2 = tau.

________________µC

Part B: Determine the amount of charge passing through the fixed point in the conductor in the time interval t1 = tau to t2 = 4tau.

________________µC

I am having a hard time understanding these problems. So if you answer please explain how you found the answers.