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11
The Nature of Light
11.1 INTRODUCTION
At the beginning of the twentieth century, two great revolutions in physics occurred
that changed the way physicists viewed the world. One is known as quantum mechan-
ics and the other is Einstein’s theory of relativity. Interestingly, they both were ini-
tially concerned with the nature of light. Quantum mechanics began with an attempt
to understand how light interacted with matter, while an integral part of relativity has
to do with the speed of light. Therefore, it is tting that before we discuss these two
great theories, we take some time to discuss light and its properties.
There has been a great ...