(a) What is the current involved when a truck battery sets in motion 720 C of charge in 4.00 s while starting an engine?

(b) How long does it take 1.00 C of charge to flow through a handheld calculator if a 0.300-mA current is flowing?

Strategy

We can use the definition of current in the equation I = ΔQ/Δt to find the current in part (a), since charge and time are given. In part (b), we rearrange the definition of current and use the given values of charge and current to find the time required.