What is the SI unit of electric current?

State the definition of average current in terms of charge and time.

A metal wire has conventional current to the left. Which way do electrons drift?

A charge of \(24\,\mathrm{C}\) crosses a wire cross-section in \(8.0\,\mathrm{s}\). Find the average current.

A steady current of \(0.40\,\mathrm{A}\) flows for \(3.0\,\mathrm{min}\). How much charge crosses a cross-section?

A wire of cross-sectional area \(2.0\times10^{-6}\,\mathrm{m^2}\) carries a uniform current \(5.0\,\mathrm{A}\). Find the current density magnitude.

The charge that has crossed a surface is \(Q(t)=0.50t^2+2.0t\), with \(Q\) in coulombs and \(t\) in seconds. Find \(I(t)\) and \(I(4.0\,\mathrm{s})\).

A wire carries current density \(\vec J=(3.0\hat\imath-4.0\hat\jmath)\times10^6\,\mathrm{A\,m^{-2}}\). Find the current through a flat area \(1.0\times10^{-6}\,\mathrm{m^2}\) whose area vector is \(\vec A=A\hat\imath\).

A current varies as \(I(t)=I_0(1-t/T)\) from \(t=0\) to \(T\). Derive the total charge that crosses a surface during this interval and interpret it as an area under a graph.

Two charge carriers cross the same surface: positive ions with current contribution \(I_+\) to the right and electrons whose drift is also to the right with magnitude contribution \(I_e\). Derive the net conventional current direction and magnitude in terms of \(I_+\) and \(I_e\), including the case split.