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(A) The current density $J$ is defined as $J = I/A$,where $I$ is the current and $A$ is the cross-sectional area.Since the current $I$ flowing through

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The strip is narrower at $P$ than at $Q$.

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(A) The current density $J$ is defined as $J = I/A$,where $I$ is the current and $A$ is the cross-sectional area.Since the current $I$ flowing through the series conductor $PQ$ is constant,the current density $J$ is inversely proportional to the cross-sectional area $A$ $(J \propto 1/A)$.From the graph,the current density is higher at $P$ and decreases towards $Q$.This implies that the cross-sectional area $A$ must be smaller at $P$ and larger at $Q$.Therefore,the strip is narrower at $P$ than at $Q$.

An electric current flows along an insulated strip $PQ$ of a metallic conductor. The current density in the strip varies as shown in the graph. Which one of the following statements could explain this variation?

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