Current
The rate of flow of electric charge through a conductor, measured in amperes (A). Defined as I = Q/t, where Q is the charge (in coulombs) flowing in time t (in seconds). Conventional current direction is defined as the direction positive charges would move (opposite to electron flow in metals).
Formula
I = ΔQ/Δt
Real World
A USB-C fast charger delivers 5 A to a MacBook battery — this means 5 coulombs of charge flow through the cable every second, transferring energy rapidly to top up the battery.
Exam Focus
In 'define current' questions, use the phrase 'rate of flow of charge' and include units — both are needed for full marks.
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