ABSTRACT
This chapter obtains a generalization applicable to a limited epoch for spectral distribution. In so doing, one must note that time and frequency are complementary; that is, a time interval of many periods is required in order to identify a corresponding frequency. The chapter discusses macroscopic power spectrum, and Cerenkov radiation by considering the radiation produced by a charged particle moving with constant velocity. A charged particle moving with a constant velocity in vacuum does not radiate. Cerenkov radiation is commonly seen in water- moderated nuclear reactors as blue light surrounding the core. The chapter illustrates a cone of Cerenkov light produced at a definite wavelength by a particle traveling with a velocity greater than the speed of light in the medium.
