Final answer:
The given equation characterizes a propagating electric field in a lossless non-magnetic medium, indicating the electric field varies in time and space with well-defined magnitude, angular frequency, wavenumber, and direction.
Step-by-step explanation:
The equation provided represents an electric field (E) propagating in a medium without loss, meaning it does not absorb or scatter the energy of the wave, which is indicative of a non-magnetic and lossless medium. The electric field is characterized by a wave equation that shows how it varies with time (t) and displacement in the y-direction (y). The key parameters in this equation are the electric field magnitude (100.0 V/m), the angular frequency of the wave (4π × 10⁶ rad/s), the wavenumber (0.1257 m⁻¹ indicating how the wave varies in space), and the direction of the electric field which is along the z-axis (a_z). The units involved are V/m for electric field strength, s for time, and m for displacement. This equation tells us that the electromagnetic wave travels with a certain frequency and spatial variation in a given medium which may have a different speed of propagation from the speed of light in a vacuum (c = 3 × 10⁸ m/s).