From the preceding discussion, it might appear easy to test the
prediction that light is an electromagnetic wave We might think that all
we needed to do was to set up an ac circuit in which the current oscillate
at the frequency of visible light, say, yellow light But, alas, that is not
possible The frequency of yellow light is about 6 × 1014 Hz, while the
frequency that we get even with modern electronic circuits is hardly about
1011 Hz