Electricity

Topics

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Sample objectives

What this unit covers

• Current, potential difference and resistance: Describe how the resistance of a filament lamp increases as filament temperature increases.
• Current, potential difference and resistance: Describe an ohmic conductor at constant temperature as having current directly proportional to potential difference.
• Current, potential difference and resistance: Explain that charge flows in a closed circuit only when the circuit includes a source of potential difference.
• Current, potential difference and resistance: Describe current as the rate of flow of electrical charge.
• Current, potential difference and resistance: Calculate resistance when potential difference and current are known.
• Current, potential difference and resistance: Use MS 3b and MS 3c skills when calculating current, potential difference and resistance.
• Current, potential difference and resistance: Interpret circuit diagrams to identify how components are connected.
• Current, potential difference and resistance: Recognise and use standard circuit symbols for common electrical components.
• Series and parallel circuits: State that the total potential difference of the power supply is shared between components in series.
• Series and parallel circuits: Construct and check series circuits using common circuit components.
• Series and parallel circuits: State that total resistance of two parallel resistors is less than the resistance of the smallest individual resistor.
• Series and parallel circuits: Identify when electrical components are connected in parallel.
• Domestic uses and safety: State that the UK domestic electricity supply is about 230 V.
• Domestic uses and safety: Explain that mains electricity is an alternating-current supply.
• Domestic uses and safety: Describe most mains appliances as being connected using a three-core cable.
• Domestic uses and safety: Explain that the neutral wire completes the circuit.
• Energy transfers: Explain why reducing current in transmission cables reduces unwanted energy transfers.
• Energy transfers: State that electrical power is transferred from power stations to consumers using the National Grid.
• Energy transfers: Identify power P in watts, potential difference V in volts, current I in amperes and resistance R in ohms.
• Energy transfers: Recall and apply the equation P = V x I.
• Energy transfers: Describe how domestic appliances transfer energy from batteries or ac mains to thermal energy stores in heating devices.
• Energy transfers: Explain how the power of a circuit device relates to energy transferred over a given time.
• Static electricity (physics only): Describe how charged objects exert forces on each other when brought close together.
• Static electricity (physics only): State that objects with different types of charge attract.
• Static electricity (physics only): Explain that the force between charged objects gets stronger as distance decreases.
• Static electricity (physics only): Explain that a charged object creates an electric field around itself.