P12.3 – Current, Electromotive Force and Potential Difference

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1. State that current is related to the flow of charge.

Current is the flow of charge (electrons) within a circuit.

2. State that the current in metals is due to a flow of electrons.

Metallic bonding is the strong attraction between closely packed positive metal ions and a ‘sea’ of delocalised electrons. These delocalised elecetrons can carry charge and move freely through giant the metal structure, thus making metals conductive of electricity.

 

3. Demonstrate understanding that a current is a rate of flow of charge, and recall and use the equation I = Q /t.

Current is the rate of flow of charge in a given point of the circuit.

I = Q ÷ t

where I=current (amperes), Q=charge (coulomb) and t=time (seconds/minutes)

 

4. Use the term potential difference (p.d.) to describe what drives the current between two points in a circuit.

Potential represents how much energy there is to drive a current through the wire and is measured in volts (v).

 

5. Distinguish between the direction of flow of electrons and conventional current.

 

At first scientists believed that electricity from the positive to the negative terminal of a battery, but then found out that it was actually the other way around- electrons flow from the negative to the positive termianl. In order to not confusing, they called the initial assumption ‘conventional current’.

 

6. Demonstrate understanding that e.m.f. is defined in terms of energy supplied by a source in driving charge round a complete circuit.

Well, learn that definition.

 

 

Notes submitted by Lintha

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