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551.


Problem 41.5 (RHK)


We have to find the inductance required with a 17-pF capacitor in order to construct an oscillator capable of generating 550-nm (i.e. visible) electromagnetic waves. We have to comment on our answer.


Solution:           Click For PDF Version

In an LC-oscillator frequency,, generated is determined by the inductance, L, and the capacitance, C, by the relation

Also, frequency, , and the wavelength, , are related to each other by the speed of light, c, as

We therefore have the relation

The oscillator is to generate waves of wavelength with a capacitor of capacitance, ; therefore, the inductance required will be

It is an extremely small inductance. Therefore, generation of visible radiation as an output of an LC-oscillator is impractical.