Define electric current and potential difference. Draw a circuit with a cell, key, bulb, ammeter and voltmeter, and explain how each meter is connected.

1. 1 · Define current in one line. Electric current is the rate of flow of charge: I = Q/t, unit ampere (A).
2. 2 · Define potential difference. Work done to move a unit positive charge between two points: V = W/Q, unit volt (V).
3. 3 · Draw the circuit. [Circuit: cell, key, bulb and ammeter in one loop; voltmeter across the bulb; + and − marked on the meters; arrow for conventional current]
4. 4 · Explain the meters.
   • Ammeter in series, so the same current passes through it.
   • Voltmeter in parallel, so it reads the potential difference across the bulb.
5. 5 · Real-life link. A phone charger rated 5 V, 2 A gives a 5 V push and up to 2 C of charge each second.
6. 6 · Close in one line. Current flows only in a closed circuit, driven by a potential difference.

Scoring tip: Use the proper symbols: long thin line for the + side of the cell, and a circle with A or V for the meters.