Induced potential, transformers and the National Grid (physics only) (HT only) common mistakes

National Grid transformer reasoning: avoid AC and DC

Treating AC and DC as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Induced potential (HT only), then explain how it links to a bar magnet and plotting compass practical and the objective to describe how a potential difference is induced across a conductor when the conductor moves relative to a magnetic field.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Induced potential (HT only), then explain how it links to a steel core electromagnet demonstration and the objective to describe how a potential difference is induced when there is a change in the magnetic field around a conductor.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Induced potential (HT only), then explain how it links to a current-carrying wire between magnetic poles and the objective to state that a current is induced if the conductor is part of a complete circuit.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Induced potential (HT only), then explain how it links to a loudspeaker coil moving in a magnetic field and the objective to describe induced potential difference and induced current as the generator effect.

National Grid transformer reasoning: avoid induced and supplied...

Treating induced and supplied current as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Induced potential (HT only), then explain how it links to an alternator producing an AC output trace and the objective to state that an induced current generates a magnetic field that opposes the original change.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Induced potential (HT only), then explain how it links to a dynamo producing a DC output trace and the objective to explain that the original change may be the movement of the conductor or the change in magnetic field.

National Grid transformer reasoning: avoid AC and DC

Treating AC and DC as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Induced potential (HT only), then explain how it links to a moving-coil microphone investigation and the objective to recall the factors that affect the size of the induced potential difference or induced current.

National Grid transformer reasoning: avoid AC and DC

Treating AC and DC as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Induced potential (HT only), then explain how it links to a step-up transformer on the National Grid and the objective to recall the factors that affect the direction of the induced potential difference or induced current.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Induced potential (HT only), then explain how it links to a step-down transformer for a low-voltage device and the objective to apply the principles of the generator effect in a given context.

National Grid transformer reasoning: avoid electromagnets and...

Treating electromagnets and permanent magnets as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Induced potential (HT only), then explain how it links to a student comparing motor and generator effects and the objective to distinguish induced current from supplied current in electromagnetic devices.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Uses of the generator effect (HT only), then explain how it links to a calculation using primary and secondary coils and the objective to state that the generator effect is used in an alternator to generate alternating current.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Uses of the generator effect (HT only), then explain how it links to a bar magnet and plotting compass practical and the objective to state that the generator effect is used in a dynamo to generate direct current.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Uses of the generator effect (HT only), then explain how it links to a steel core electromagnet demonstration and the objective to explain how the generator effect is used in an alternator to generate ac.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Uses of the generator effect (HT only), then explain how it links to a current-carrying wire between magnetic poles and the objective to explain how the generator effect is used in a dynamo to generate dc.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Uses of the generator effect (HT only), then explain how it links to a loudspeaker coil moving in a magnetic field and the objective to draw graphs of potential difference generated in a coil against time.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Uses of the generator effect (HT only), then explain how it links to an alternator producing an AC output trace and the objective to interpret graphs of potential difference generated in a coil against time.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Uses of the generator effect (HT only), then explain how it links to a dynamo producing a DC output trace and the objective to distinguish ac output from dc output using potential difference-time graphs.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Uses of the generator effect (HT only), then explain how it links to a moving-coil microphone investigation and the objective to apply WS 1.4 when interpreting diagrams and graphs of generator-effect devices.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Microphones (HT only), then explain how it links to a step-up transformer on the National Grid and the objective to state that microphones use the generator effect.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Microphones (HT only), then explain how it links to a step-down transformer for a low-voltage device and the objective to describe how pressure variations in sound waves are converted into variations in current in electrical circuits.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Microphones (HT only), then explain how it links to a student comparing motor and generator effects and the objective to explain how a moving-coil microphone works.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Microphones (HT only), then explain how it links to a calculation using primary and secondary coils and the objective to link movement of a coil in a magnetic field to induced potential difference in a microphone.

National Grid transformer reasoning: avoid motors and generators

Treating motors and generators as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Microphones (HT only), then explain how it links to a bar magnet and plotting compass practical and the objective to distinguish microphone generator-effect operation from loudspeaker motor-effect operation.

National Grid transformer reasoning: avoid primary and secondary...

Treating primary and secondary coils as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a steel core electromagnet demonstration and the objective to describe a basic transformer as a primary coil and a secondary coil wound on an iron core.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a current-carrying wire between magnetic poles and the objective to state that iron is used in the core because it is easily magnetised.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a loudspeaker coil moving in a magnetic field and the objective to recognise that knowledge of laminations and eddy currents in the core is not required.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to an alternator producing an AC output trace and the objective to explain how an alternating current in one coil induces a current in another coil.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a dynamo producing a DC output trace and the objective to explain how the effect of an alternating current in one coil inducing a current in another is used in transformers.

National Grid transformer reasoning: avoid AC and DC

Treating AC and DC as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a moving-coil microphone investigation and the objective to state that the ratio of the potential differences across the primary and secondary coils depends on the ratio of the number of turns on each coil.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a step-up transformer on the National Grid and the objective to recall and apply the transformer equation Vp / Vs = np / ns.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a step-down transformer for a low-voltage device and the objective to identify Vp and Vs as potential differences in volts.

National Grid transformer reasoning: avoid primary and secondary...

Treating primary and secondary coils as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a student comparing motor and generator effects and the objective to identify np and ns as the number of turns on the primary and secondary coils.

National Grid transformer reasoning: avoid primary and secondary...

Treating primary and secondary coils as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a calculation using primary and secondary coils and the objective to describe a step-up transformer as having secondary potential difference greater than primary potential difference.

National Grid transformer reasoning: avoid primary and secondary...

Treating primary and secondary coils as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a bar magnet and plotting compass practical and the objective to describe a step-down transformer as having secondary potential difference less than primary potential difference.

National Grid transformer reasoning: avoid AC and DC

Treating AC and DC as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a steel core electromagnet demonstration and the objective to explain how the ratio of potential differences across the two coils depends on the ratio of turns on each coil.

National Grid transformer reasoning: avoid primary and secondary...

Treating primary and secondary coils as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a current-carrying wire between magnetic poles and the objective to calculate primary potential difference, secondary potential difference, primary turns or secondary turns using transformer ratios.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a loudspeaker coil moving in a magnetic field and the objective to state that if transformers were 100 percent efficient, the electrical power output would equal the electrical power input.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to an alternator producing an AC output trace and the objective to recall and apply the equation Vp x Ip = Vs x Is for a 100 percent efficient transformer.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a dynamo producing a DC output trace and the objective to identify Vp x Ip as power input and Vs x Is as power output.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a moving-coil microphone investigation and the objective to identify transformer power input and output in watts.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a step-up transformer on the National Grid and the objective to calculate the current drawn from the input supply to provide a particular power output.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a step-down transformer for a low-voltage device and the objective to apply the equation linking potential differences and turns to current and power transfer.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a student comparing motor and generator effects and the objective to relate transformer calculations to the advantages of power transmission at high potential differences.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a calculation using primary and secondary coils and the objective to apply MS 3b and MS 3c when using transformer equations.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a bar magnet and plotting compass practical and the objective to apply MS 1c, MS 3b and MS 3c when linking transformer calculations to power transmission.

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a steel core electromagnet demonstration and the objective to recognise that transformer equations are given on the Physics equation sheet.