Re: Why can the frequencies of radio waves be controlled but not visible light?

Dear Paul,

In a low frequency circuit everything happens in discrete  circuit 
elements and the wiring can be ignored since it has little resistance, 
capacitance, or inductance.  As the frequency of a circuit increases this 
approximation breaks down.  By the time you get to frequencies in the 
microwave region (around 100 million cycles/sec)the inductance, 
capacitance and resistance of the wires become so large that it is almost 
impossible to send signals down them.  At optical frequencies, which are 
ten million times faster still, it is completely hopeless!

Larry