Electromagnetism and Energy
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Lesson Order
- 4-ELM-01 Electromagnets.
- 4-ELM-02 Electric Motors.Left hand rule.
- 4-ELM-03 Electric motors. Class practical
- 4-ELM-04 Electromagnetic induction.
- 4-ELM-05 Transformers.
- 4-ELM-06 Revision and test
- 4-ELM-07 Work done.
- 4-ELM-08 Kinetic and potential energy. Conservation of energy.
- 4-ELM-09 Power
- 4-ENG-10 Revision and test
Topics covered
- appreciate that there is a force on a charged particle when it moves in a magnetic field as long as its motion is not parallel to the field
- recall that a force is exerted on a current-carrying wire in a magnetic field, and how this effect is applied in simple d.c.electric motors and loudspeakers
- use the left hand rule to predict the direction of the resulting force when a wire carries a current perpendicular to a magnetic field
- recall that the force on a current-carrying conductor in a magnetic field increases with teh strength of the field and with the current
- electromagnetic induction
- recall that a voltage is induced in a conductor or a coil when it moves through a magnetic field or when a magnetic field changes though it; recall the factors which affect the size of the induced voltage
- describe the generation of electricity by the rotation of magnet within a coil of wire and a coil of wire within a magnetic field; describe the factors which affect the size of the induced voltage
- recall the structure of a transformer and understand that a transformer changes the size of an alternating voltage by having different numbers of turns on the input and output sides
- explain the use of step-up and step-down transformers in the large-scale generation and transmission of electrical energy
- recall and use the relationship between input(primary) and output(secondary) voltages and the turns ratio for a transformer: Primary voltage/secondary voltage = primary turns/secondary turns
- input power = output power for 100% efficiency
- Recall and use Weight = mass * gravity
- Weight is always acting downwards (when working with diagrams)
- recall and use work done = force * distance moved in the direction of the force
- understand that work done = energy transferred
- understand the difference between the gravitational and kinetic energy
- gravitational potential energy = mass * gravity * height
- kinetic energy = 1/2 * mass * velocity
- understand how conservation of energy produces a link between GPE, Ke and work done
- describe power as the rate of transfer of energy or rate of doing work
- Power = work done / time
