# AQA AS Physics A Electric current

NOT FINISHED YET, BUT EYES ARE STARTING TO HURT SO WILL FINISH OFF TOMORROW :) X

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• Created by: Charlotte
• Created on: 26-11-12 18:58
• Electric Current
• Current and Charge
• Current is the rate of flow of charge. The current is caused by the movement of charge carriers.
• The electrons in the outer shells of atoms in metal are delocalised when they bond, this means  that they are able to move within the metal and carry a charge.
• In solutions ions are able to move which means that they can carry a charge.
• Current is measured in Amperes (A) and is a base unit.
• Charge is measured in Coulombs (C). 1C is equal to the charge flow in 1 second when the current is 1A.
• Charge  Q = Current I x time t.
• Potential Difference and Power.
• The battery supplies each electron with potential energy.
• When an electron passes through a component, work is done, the amount of work done is equal to the loss of pd.
• Potential difference is the work done per unit charge.
• Work done W = Charge Q x pd V.
• The emf of a source of electricity is the electrical energy produced per unit charge passing throught the source
• Potential difference is the loss of energy. EMF is the gain of energy.
• Resistance
• Components and their characteristics