- Current section: Introduction
- Learning outcomes
- 1 Maxwell's greatest triumph
- 2 The equation of continuity
- 3 The Ampère–Maxwell law
- 4 Maxwell's equations
- 5 Let there be light!
- 6 Appendix: a note on displacement current density
- 7 Unit summary
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James Clerk Maxwell
James Clerk Maxwell (1831-1879) is arguably the father of electromagnetism, and...
James Clerk Maxwell (1831-1879) is arguably the father of electromagnetism, and unarguably one of the greatest physicists ever. Einstein called Maxwell's equations 'the most important event in physics since Newton's time, not only because of their wealth of content, but also because they form a pattern for a new type of law'. This unit will examine Maxwell's greatest triumph, the prediction that electromagnetic waves can propagate vast distances through empty space and the realisation that light is itself an electromagnetic wave.
By the end of this unit you should be able to:
- explain the meaning of the emboldened terms and symbols, and use them appropriately;
- state the equation of continuity and use it in simple problems;
- state the conditions under which Ampère's law is true and explain why it does not apply more generally;
- state the Ampère–Maxwell law and explain why it has a greater domain of validity than Ampère's law;
- state and name the differential versions of Maxwell's four laws of electromagnetism;
- recall the properties of linearly polarised plane monochromatic electromagnetic waves in empty space, including their transverse nature, speed and energy flux.
James Clerk Maxwell
James Clerk Maxwell produced a unified theory of the electromagnetic field and used it to show that light is a type of electromagnetic wave. This prediction dates from the early 1860s when Maxwell was at King's College, London. Shortly afterwards Maxwell decided to retire to his family estate in Galloway in order to concentrate on research, unhindered by other duties. He was lured out of retirement in 1871, when he became the first professor of experimental physics in the Cavendish Laboratory, Cambridge. Given Maxwell's present status as one of the greatest of all physicists, it is astonishing to learn that he was the third choice for this job. Incidentally, Clerk Maxwell (without a hyphen) is a surname; Maxwell's father, John Clerk, simply appended ‘Maxwell’ to his own name in order to smooth a legal transaction.
This unit is from our archive and it is an adapted extract from Topics in the history of mathematics (STM359) which is no longer in presentation. If you wish to study formally at The Open University, you may wish to explore the courses we offer in this.