Quantum Phenomena and Wave Character

Numerous mechanical devices in our everyday world assert the validity of the classical mechanical analyses that have helped in the design of such devices. However, we caimot beforehand be assured that the mechanics of a clock pendulum, for instance, are the same when the size of the pendulum system is reduced (or increased) well beyond the limits of our experience. The mass of an atom may be as little as g, and this is a very different size than that of objects we see and touch. Mechanical behavior in the world of such very tiny particles is, in fact, different. 

It was no doubt xmsahsfying to many scientists during the early part of the century that basic physical laws worked out over almost two centuries did not hold for the tiny world of electrons and atoms. Today, we see the classical picture as a special case of broader theories of matter and radiahon. It took studies of the tiny-particle world and the introduction of several new concepts to develop the more encompassing theories. This was because key features of the quantum world are manifested in ways not directly perceptible in our everyday world. 

Parhcle diffrachon was an important stepping stone in the understanding of tiny-parhcle mechanics. The parhcles used for a diffrachon experiment are free particles, meaning they are not subject to a potenhal. Electrons, for instance, would first have to be stripped away from some atoms or molecules. Observing diffraction requires that all the particles in the 

X is the de Broglie wavelength (Louis Victor de Broglie, France, 1892-1987). The proportionality constant of this relation, h, is a fundamental constant of nature, Planck s constant (Max Planck, Germany, 1858-1947). The value of h is 6.626069 x 10 J s. 

Let us find the de Broglie wavelength for an object from our day-to-day world, a bowling ball rolling at 36 km h X If the mass of the ball is 8 kg, then the linear momentum of this particle is 

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