AQA GCSE Current and Electrical Charge

AQA GCSE Current and Electrical Charge

Electric Current

Electric current is the flow of charge around a circuit. Circuit diagram showing the difference between electron flow and conventional current flow The cell or battery of a circuit makes these charges flow around the circuit. Conventional current flow is from positive to negative, electron flow however is from negative to positive.

(There is a reason for the difference, but you don’t need to know it!)

The cell or battery makes the charges flow around the circuit, the potential difference or voltage provides the energy to push and pull the charges to flow around the circuit.
Metallic Structure

Metallic structure is a giant structure made up of positive metal ions and delocalised electrons. These delocalised electrons (free electrons) are able to move through the structure, carrying charge.

Metallic structure showing positive metal ions and delocalised electrons

Electric Charge

Electric charge is the total amount of current that flows in a time period.

At GCSE electrical charge is defined on 1 amp flowing for 1 second, which means that a total charge of 1 coulomb is transferred.

Imagine water flowing in a river respresents the current, then the total water flow, would be the total charge. 

Charge formula triangle. Charge = current x time

Electrical charge, Q = Current, I x Time,t

(Coulombs,C)               (Amps,A)    (Seconds,s)

Practice Questions

1.State which direction conventional current flows.

2. What makes the current flow around a circuit?

3. Why is copper a good conductor of electricity?

4. Describe metallic structure.

5. A 3 amp light bulb is switched on for 2 minutes. Calculate the total electrical charge transferred.