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Led by Michael Faraday Simulacrum
Five tutorials covering AQA GCSE Physics §4.7 Magnetism and Electromagnetism — permanent and induced magnetism, electromagnetism from current-carrying wires, the motor effect, the generator effect, and transformers — taught by simulacra of the physicists whose 19th-century work turned electromagnetism from laboratory curiosity into the infrastructure of the modern world.
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Led by Michael Faraday Simulacrum
The question
What is a magnetic field, and why does a compass needle always point north?
Territory
poles of a magnet (where forces are strongest) · attraction between unlike poles, repulsion between like poles · attraction and repulsion as non-contact forces · permanent magnets vs induced magnets · induced magnetism always causes attraction · induced magnets lose magnetism quickly when the external field is removed · magnetic materials: iron, steel, cobalt, nickel · the magnetic field as the region where a force acts on another magnet or magnetic material · field strength varies with distance from the magnet · field strongest at the poles · field direction as the direction a north pole would be pushed · field lines from north to south by convention · drawing field patterns using a compass or iron filings · the magnetic compass as a small bar magnet · Earth's magnetic field and the behaviour of a compass
Outcome
The student can describe the attraction and repulsion between magnetic poles, distinguish permanent from induced magnets, draw the magnetic field pattern of a bar magnet with correct direction, plot a field using a compass, and explain how the compass behaviour reveals Earth's magnetic field. (AQA 4.7.1.1, 4.7.1.2)
Led by André-Marie Ampère Simulacrum
The question
A current flowing through a wire produces a magnetic field around the wire — why, and how can this be put to use?
Territory
a current through a wire produces a magnetic field around the wire · field strength depends on current and on distance from the wire · demonstrating the magnetic effect of a current (compass near wire) · field pattern for a straight current-carrying wire (concentric circles, direction convention) · solenoid: wire wound into a coil · field inside a solenoid is strong and uniform · field around a solenoid resembles that of a bar magnet (with north and south ends) · field pattern diagrams for solenoids · adding an iron core to make an electromagnet · why the iron core increases field strength (induced magnetism inside the core) · (physics only) interpreting diagrams of electromagnetic devices to explain their operation
Outcome
The student can describe how a current produces a magnetic field, draw the field pattern for a straight wire and a solenoid with correct direction, explain how a solenoid and an iron core together make an electromagnet, and (physics only) interpret diagrams of electromagnetic devices. (AQA 4.7.2.1)
Led by Nikola Tesla Simulacrum
The question
When a current-carrying wire is placed in a magnetic field, it experiences a force — how big, in which direction, and how can this be turned into a motor?
Territory
the motor effect: a current-carrying conductor in a magnetic field experiences a force · Fleming's left-hand rule (first finger = field, second finger = current, thumb = force) · factors affecting the size of the force (current, field strength, length of conductor) · F = BIl for a conductor at right angles to the field · magnetic flux density B in tesla, T · the force equation applied · a current-carrying coil in a field experiences a torque → rotation · this is the basis of an electric motor · explaining rotation from the force on opposite sides of the coil · (physics only) the moving-coil loudspeaker: electric signal drives a coil attached to a diaphragm, producing sound · (physics only) headphones as small loudspeakers
Outcome
The student can describe the motor effect, apply Fleming's left-hand rule, apply F = BIl, explain how a current-carrying coil in a magnetic field causes rotation in an electric motor, and (physics only) explain how a moving-coil loudspeaker and headphones work. (AQA 4.7.2.2, 4.7.2.3, 4.7.2.4)
Led by Michael Faraday Simulacrum
The question
If a current creates a magnetic field, can a magnetic field create a current?
Territory
the generator effect: induced potential difference across a conductor when it moves relative to a magnetic field, or when the field around it changes · induced current if the conductor is part of a complete circuit · induced current generates a magnetic field opposing the original change · factors affecting the size of induced pd/current (speed of relative motion, field strength, number of turns in a coil) · factors affecting the direction of induced pd/current · applying the generator effect in context · alternator generates ac using slip-rings · dynamo generates dc using a split-ring commutator · drawing and interpreting graphs of induced pd against time · moving-coil microphone: pressure variations in sound → coil motion → induced current variations
Outcome
The student can describe the generator effect, apply its principles to a moving conductor in a field, distinguish alternators from dynamos, draw and interpret pd-time graphs for both, and explain how a moving-coil microphone works. (AQA 4.7.3.1, 4.7.3.2, 4.7.3.3)
Led by James Clerk Maxwell Simulacrum
The question
How does a transformer change the voltage of an alternating-current supply — and why is that the reason the National Grid works?
Territory
basic transformer: primary coil and secondary coil wound on an iron core · why iron is used (easily magnetised) · details of laminations and eddy currents are NOT required · how an alternating current in the primary induces an alternating current in the secondary via the changing magnetic field · Vp/Vs = np/ns (given on equation sheet) · step-up transformer (Vs > Vp) and step-down transformer (Vs < Vp) · for an ideal (100% efficient) transformer: Vs × Is = Vp × Ip · calculating the current drawn from the input supply to produce a particular power output · applying the turns-ratio and power equations together · why the National Grid uses high transmission voltages (low I means low I²R losses in cables) · the full pipeline: power station → step-up transformer → transmission lines → step-down transformer → domestic supply (cross-reference to Course 2 Module 5)
Outcome
The student can describe a basic transformer, apply both the turns-ratio equation and the ideal-transformer power equation, calculate input current for a required output power, and explain why high-voltage transmission is efficient — linking the transformer's function to the operation of the National Grid. (AQA 4.7.3.4)