The motor effect revision notes

The motor effect

The motor effect revision notes for AQA GCSE Physics 8463 Unit 4.7 Magnetism and Electromagnetism.

Core method: identify the device or field pattern, state the direction or equation where required, then connect the result to a physical consequence.

Focus 1: In Electromagnetism, students revise how to (Physics only) Apply WS 1.4 when explaining electromagnetic devices from diagrams. Key terms include electromagnet. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 2: In Electromagnetism, students revise how to (Physics only) Interpret diagrams of electromagnetic devices in order to explain how they work. Key terms include electromagnet. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 3: In Electromagnetism, students revise how to apply WS 2.2 when drawing magnetic field patterns for a current-carrying wire and solenoid. Key terms include current, magnetic field, field pattern, and solenoid. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 4: In Electromagnetism, students revise how to define an electromagnet as a solenoid with an iron core. Key terms include solenoid, iron core, and electromagnet. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 5: In Electromagnetism, students revise how to describe how shaping a wire to form a solenoid increases the strength of the magnetic field created by a current. Key terms include magnetic field, current, and solenoid. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 6: In Electromagnetism, students revise how to describe how the magnetic effect of a current can be demonstrated. Key terms include current and magnetic effect. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 7: In Electromagnetism, students revise how to describe how the strength of the magnetic field around a wire depends on current through the wire. Key terms include current and magnetic field. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 8: In Electromagnetism, students revise how to describe how the strength of the magnetic field around a wire depends on distance from the wire. Key terms include magnetic field. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 9: In Electromagnetism, students revise how to describe the magnetic field around a solenoid as having a similar shape to that of a bar magnet. Key terms include magnetic field and solenoid. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 10: In Electromagnetism, students revise how to draw the magnetic field pattern for a solenoid, showing the direction of the field. Key terms include magnetic field, solenoid, and field pattern. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 11: In Electromagnetism, students revise how to draw the magnetic field pattern for a straight wire carrying a current. Key terms include current, magnetic field, and field pattern. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 12: In Electromagnetism, students revise how to explain how a solenoid arrangement can increase the magnetic effect of the current. Key terms include solenoid, magnetic effect, and current. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 13: In Electromagnetism, students revise how to state that adding an iron core increases the strength of the magnetic field of a solenoid. Key terms include magnetic field, solenoid, and iron core. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 14: In Electromagnetism, students revise how to state that the magnetic field inside a solenoid is strong and uniform. Key terms include magnetic field and solenoid. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 15: In Electromagnetism, students revise how to state that when a current flows through a conducting wire a magnetic field is produced around the wire. Key terms include current, conducting wire, and magnetic field. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 16: In Fleming's left-hand rule (HT only), students revise how to (HT only) Apply MS 3b and MS 3c when using the motor-effect equation. Key terms include HT only. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 17: In Fleming's left-hand rule (HT only), students revise how to (HT only) Describe the motor effect as the force on a current-carrying conductor placed in a magnetic field. Key terms include HT only, motor effect, current, and conductor. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 18: In Fleming's left-hand rule (HT only), students revise how to (HT only) Identify force F in newtons, magnetic flux density B in tesla, current I in amperes and length l in metres. Key terms include HT only, force, current, and magnetic flux density. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 19: In Fleming's left-hand rule (HT only), students revise how to (HT only) Rearrange F = B x I x l to calculate magnetic flux density, current or length where appropriate. Key terms include current, magnetic flux density, and HT only. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 20: In Fleming's left-hand rule (HT only), students revise how to (HT only) Recall and apply the equation F = B x I x l for a conductor at right angles to a magnetic field. Key terms include HT only, conductor, and magnetic field. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 21: In Fleming's left-hand rule (HT only), students revise how to (HT only) Recall that the force depends on magnetic flux density, current and length of conductor in the field when the conductor is at right angles to the field. Key terms include current, magnetic flux density, conductor, and HT only. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 22: In Fleming's left-hand rule (HT only), students revise how to (HT only) Recall the factors that affect the size of the force on a current-carrying conductor. Key terms include HT only, force, current, and conductor. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 23: In Fleming's left-hand rule (HT only), students revise how to (HT only) Recognise that the motor-effect equation is given on the Physics equation sheet. Key terms include HT only. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 24: In Fleming's left-hand rule (HT only), students revise how to (HT only) State that the magnet producing the field and the conductor exert a force on each other. Key terms include HT only, force, and conductor. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 25: In Fleming's left-hand rule (HT only), students revise how to (HT only) Use Fleming's left-hand rule to represent the relative orientation of force, current and magnetic field. Key terms include Fleming's left-hand rule, magnetic field, HT only, and force. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 26: In Electric motors (HT only), students revise how to (HT only) Describe rotation of a current-carrying coil in a magnetic field as the basis of an electric motor. Key terms include electric motor, coil, current, and magnetic field. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 27: In Electric motors (HT only), students revise how to (HT only) Explain how the force on a conductor in a magnetic field causes rotation of the coil in an electric motor. Key terms include HT only, electric motor, coil, and magnetic field. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 28: In Electric motors (HT only), students revise how to (HT only) Link opposite forces on the sides of a current-carrying coil to the turning effect in an electric motor. Key terms include HT only, electric motor, coil, and current. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 29: In Electric motors (HT only), students revise how to (HT only) State that a coil of wire carrying a current in a magnetic field tends to rotate. Key terms include HT only, coil, current, and magnetic field. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 30: In Electric motors (HT only), students revise how to (HT only) Use motor-effect reasoning to explain the operation of a simple electric motor. Key terms include HT only and electric motor. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 31: In Loudspeakers (physics only) (HT only), students revise how to (Physics only) (HT only) Describe how variations in current in an electrical circuit are converted into pressure variations in sound waves. Key terms include physics only, HT only, sound wave, and pressure variation. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 32: In Loudspeakers (physics only) (HT only), students revise how to (Physics only) (HT only) Explain how a moving-coil loudspeaker works. Key terms include physics only, HT only, loudspeaker, and coil. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 33: In Loudspeakers (physics only) (HT only), students revise how to (Physics only) (HT only) Explain how headphones use the motor effect to produce sound. Key terms include physics only, HT only, headphone, and motor effect. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 34: In Loudspeakers (physics only) (HT only), students revise how to (Physics only) (HT only) Link the motion of the coil or cone to pressure variations in the surrounding air. Key terms include HT only, coil, physics only, and pressure variation. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Focus 35: In Loudspeakers (physics only) (HT only), students revise how to (Physics only) (HT only) State that loudspeakers and headphones use the motor effect. Key terms include loudspeaker, headphone, motor effect, and physics only. A strong answer names the magnetic field, force, current, coil or transformer quantity involved, describes the physical sequence, and keeps concept boundaries explicit.

Exam technique: for transformer calculations, write Vp / Vs = Np / Ns or Vp x Ip = Vs x Is, substitute values with units, rearrange carefully, and state whether the result refers to the primary or secondary coil. For motor and generator questions, distinguish supplied current from induced current and distinguish AC from DC.