Electromagnetic radiation dual nature

DUAL NATURE OF ELECTROMAGNETIC RADIATION WAVES AND PARTICLES... 

Electromagnetic radiation can be absorbed or emitted. The absorption of ultraviolet radiation by our skin may cause sunburn. When we cook food in a microwave oven, the absorption of microwave radiation by the water in the food causes the water molecules to vibrate, generating heat that cooks the food. However, when electromagnetic radiation is absorbed or emitted by matter, it behaves more like a stream of particles than as a wave motion. These particles are called photons and so electromagnetic radiation can be considered both as a stream of photons and as waves with characteristic properties, such as wavelength (1) and frequency (/). Therefore we say that electromagnetic radiation has a dual nature wave motion and streams of photons. 

The experimental evidence discussed so far in this chapter leaves no possible doubt for the dual nature of electromagnetic radiation. It does not however make it easy to understand. How can something behave sometimes as waves, sometimes as particles This question will be raised again in connection with electrons and other microscopic particles in Chapter 2, and the difficulties discussed in more detail there (see Section 2.4). At this point, it is appropriate to discuss some ideas which, without giving a complete answer, go part of the way towards one. 

Electromagnetic radiation, which was previously thought to exhibit only wave properties, seems to show certain characteristics of particulate matter as well. This phenomenon, illustrated in Fig. 12.6, is sometimes referred to as the dual nature of light. 

According to quantum mechanics, electromagnetic radiation has a dual and seemingly contradictory nature. 

This dual wave/particle nature is the basis of the quantum theory of electromagnetic radiation, which states that radiant energy can be absorbed or emitted only in discrete packets called quanta or photons. The energy E of each photon is given by... 

Although shown to have some serious flaws and long since abandoned, the Bohr model laid the groundwork for the more sophisticated theories of atomic structure that are accepted today and introduced the all-important concept that only specific energy states are allowed for an electron in an atom. Like electromagnetic radiation, electrons in atoms are now visualized as having a dual wave/particle nature. 

The Compton scattering was the first observation of the dual - wave and particle - nature of electromagnetic radiation. 

In 1905, Albert Einstein expanded on Planck s theory by introducing the radical idea that electromagnetic radiation has a dual wave-particle nature. Light exhibits many wavelike properties, but it can also be thought of as a stream of particles. Each particle carries a quantum of energy. 

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