GCSE Physics - Electricity

• The current is the rate at which charge flows through an object.
• Potential difference is the energy transferred per unit charge between two points on a circuit
• A circuit is complete when there are no breaks in the path that electrons take from one end to another, allowing them to flow around the loop.
• Electric potential difference (V) = Energy transferred / Charge
• Current (I) = Charge / Time
• Current can be calculated using the equation Current = Charge / Time
• Power is the rate at which electrical energy is used or supplied by a source
• Electric circuits can be series or parallel.
• Electrical resistance is the opposition to the flow of electric current
• In a series circuit, all components are connected together in a single chain.
• Resistance (R) = Voltage / Current
• In a parallel circuit, components are connected by separate paths so that they do not have to pass through every component.
• Resistors are components that limit the amount of current flowing through them, they have a fixed value of resistance
• Power (P) = Potential Difference x Current
• Ohm's law states that the current through a component is directly proportional to the voltage across it if its temperature remains constant
• Resistance is measured in ohms (Ω)
• In a series circuit, all components are connected in a row with only one pathway for current to follow.
• The power rating of an appliance tells us how much current it will draw from the mains supply
• The total resistance of a series circuit is equal to the sum of the individual resistances.
• In a parallel circuit, multiple paths exist for the current to travel through.
• Potential dividers consist of two resistors in series with a voltage supply.
• Resistance is measured in ohms, represented as Ω
• A fuse is a safety device designed to break an electrical circuit when too much current flows through it.
• The total resistance of two resistors in parallel is less than either one on its own.
• The power rating on an appliance tells us how much energy it uses per second when switched on
• An ammeter measures the current passing through a circuit
• A fuse is used as an overload protection device which melts when too much current flows through it
• The symbol for potential difference is V or U
• The total potential difference around a complete circuit must be zero as energy cannot be created or destroyed.
• A parallel circuit has two or more paths for the current to flow along.
• When a fuse blows, it breaks the circuit and stops any further flow of electricity.
• When bulbs are wired in parallel, they share the same potential difference but their currents add up.
• Current is measured in amps, represented as A
• An ammeter measures the amount of charge passing through it per second.
• Voltage is measured in volts, represented as V
• A voltmeter measures potential difference across its terminals.
• Power is measured in watts, represented as W
• Power = Current x Voltage (Watts)
• A voltmeter measures potential difference across components or circuits
• When connecting an ammeter into a circuit, it must be connected in series so that all the current passes through it