Science (086) — AI-generated practice question

When the phenomenon of electricity was first studied, electrons were not yet discovered. Scientists assumed electric current to be the flow of positive charges, and the direction of their flow was taken as the direction of current. This convention was established and universally accepted.

Later, when electrons were discovered as the actual charge carriers in metallic conductors, it was found that they flow from the negative terminal to the positive terminal of a cell. To maintain consistency with the already established convention, the direction of conventional current is taken as opposite to the direction of electron flow (i.e., from positive to negative terminal).

Source: Chapter 11 – Electricity, Section 11.1 Electric Current and Circuit

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• The examiner expects two key points: (1) historical reason — electrons were unknown when the convention was set, so positive charge flow was assumed; (2) to maintain the established convention, current direction is kept opposite to electron flow.
• Mention both points clearly for full 2 marks.
• Do not confuse "conventional current" with actual electron movement — state both directions explicitly.