After studying this chapter students will be able to:
describe the production of electricity by magnetism.
explain that induced emf's can be generated in two ways.
(i) by relative movement (the generator effect).
(ii) by changing a magnetic field (the transformer effect).
infer the factors affecting the magnitude of the induced emf.
state Faraday's law of electromagnetic induction.
account for Lenz's law to predict the direction of an induced current and
relate to the principle of conservation of energy.
apply Faraday's law of electromagnetic induction and Lenz's law to solve
problems.
explain the production of eddy currents and identify their magnetic and
heating effects.
explain the need for laminated iron cores in electric motors, generators and
transformers.
explain what is meant by motional emf. Given a rod or wire moving
through a magnetic field in a simple way, compute the potential difference
across its ends.
define mutual inductance (M) and self-inductance (L), and their unit
henry.
• · describe the main components of an A.C-generator and explain how it
works.
describe the main features of an A.C electric motor and the role of each
feature.
explain the production of back emf in electric motors.
describe the construction of a transformer and explain how it works.
• identify the relationship between the ratio of the number of turns in the
primary and secondary coils and the ratio of primary to secondary
voltages.
describe how step-up and step-down transformers can be used to ensure
efficient transfer of electricity along cables.
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