Atomic, molecular, and optical physics the origin of the index of refraction treated an electron in an atomic system classically according to the model of Paul Drude and Hendrik Lorentz. The theory was developed to attempt to provide an origin for the wavelength-dependent refractive index "n" of a material. In this model, incident electromagnetic waves forced an electron bound to an atom to oscillate. The amplitude of the oscillation would then have a relationship to the frequency of the incident electromagnetic wave and the resonant frequencies of the oscillator. The superposition of these emitted waves from many oscillators would then lead to a wave which
Amplitude panning by a pair of microphones to the amplitude difference of in-phase input signals to two loudspeakers. Assuming free field sound propagation, it has been shown that the sound field presented by these two transducers can deliver an appropriate phase difference between the positions of listener’s ears at low frequencies, where the relation between the position of phantom image and the corresponding amplitude ratio may be summarized by the so-called ‘sine law’ (similarly, the tangent law). The system was designed to work approximately below 1 kHz, above which the given phase difference becomes ambiguous, and so does the position of the