Consider a conductor with a non-uniform cross-sectional area. If a steady current flows through it, which of the following quantities remains constant along the length of the conductor?

In a closed circuit, the current $I$ (in ampere) at an instant of time t(in second) is given by $I = 4 - 0.08\,\,t$. The number of electrons flowing in ${\rm{50}}\,\,{\rm{s}}$ through the cross-section of the conductor is

If the electric current through an electric bulb is ${\rm{3}}{\rm{.2 }}\,{\rm{A}}$, the number of electrons flow through it in one second is