The End of Classical Mechanics

Calculate the de Broglie wavelength of a 1000-kg automobile traveling at 100 kilometers per hour and of an electron traveling at 1% of the speed of light (0.01c = 3.00 X 10 m/s). 

Here we are substituting into the de Broglie equation and are induding conversions from km to m and from hr to. Note how the units cancel to give mis as the ultimate velodty. 

This wavelength is about the size of a large atom. 

The de Broglie wavelength of the automobile is unnoticeable even using modern methods. The de Broglie wavelength of the electron is similar to that of X rays, which are certainly noticeable under the right conditions. 

De Broglie s insight and the Davisson-Germer experiment ultimately pointed out that matter has wave properties. For large pieces of matter, the wave properties can be ignored, but for small pieces of matter like electrons, they cannot be. Because classical mechanics did not consider matter as waves, it was inadequate to describe the behavior of matter. 

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