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The River of Electrons
⚡ The River of Electrons
Here's something that surprises most people: electrons in a wire move INCREDIBLY slowly — about 1 millimetre per second! So how does a light come on instantly when you flick a switch? Because the wire is already FULL of electrons. When you connect the circuit, they ALL start moving at once — like a tube full of marbles. Push one in at one end, and one pops out the other end immediately. The battery doesn't "send" electrons — it provides the push that makes electrons already in the wire start flowing.
Understanding Current and Charge
Current is the rate of flow of charge — how much charge passes a point per second.
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🧠 Memory Aid
For Q = I × t — remember "QUIT":
Q = I × t — the "QUIck Time" an electron takes to flow (Q charges, I current, t time)
Conventional current direction — "Positive goes Positive":
Conventional current always flows out of the Positive terminal and in through the negative. The Positive starts the journey.
Ammeter in Series — "A is Alone in line":
The Ammeter goes Along the single path — it's in the series loop, never branching off.
Now try it yourself
Quiz · Question 1 of 19
What is electric current?
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This topic in real past papers
Every real exam question we've found on current & charge, with a full worked answer.