This article is about the term as it applies to neuroscience. It’s called F wave because it was initially recorded in the foot muscles. Because a different population of anterior horn cells is stimulated with each stimulation, each F wave have a slightly different shape, amplitude and latency. Several measurements can be done on the F responses, including minimal properties of waves pdf maximal latencies, and F wave persistence.
The minimal F wave latency is typically 25-32 ms in the upper extremities, and 45-56 ms in the lower extremities. 13: H reflexes and F waves: physiology and indications. Nerve conduction studies and their clinical applications. Electromyography and Neuromuscular disorders, Elsevier, 2005. This page was last edited on 19 August 2015, at 20:34.
This article is about waves in the scientific sense. A wave is a disturbance that transfers energy through matter or space. There are two main types of waves. This keeps the molecules from continuing to travel in the direction of the wave. The mathematical form of this equation varies depending on the type of wave.
However, a vibration is not necessarily a wave. It may appear that the description of waves is closely related to their physical origin for each specific instance of a wave process. This difference in origin introduces certain wave characteristics particular to the properties of the medium involved. Other properties, however, although usually described in terms of origin, may be generalized to all waves. On the other hand, if all the parts were independent, then there would not be any transmission of the vibration and again, no wave motion. Consider the string to have a single spatial dimension.
Animation of two waves, the green wave moves to the right while blue wave moves to the left, the net red wave amplitude at each point is the sum of the amplitudes of the individual waves. To understand them, one must consider several types of waveform. For simplification, examination is restricted to one dimension. This shows a wave with the Group velocity and Phase velocity going in different directions. However, an exception occurs at the location where the argument φ of the exponential varies slowly. In the illustration to the right, this is the maximum vertical distance between the baseline and the wave. The units of the amplitude depend on the type of wave.
In other words, the frequency and period of a wave are reciprocals. The analysis of the wave can be based upon comparison of the local wavelength with the local water depth. The sinusoid is defined for all times and distances, whereas in physical situations we usually deal with waves that exist for a limited span in space and duration in time. As a result, the simple case of a single sinusoidal wave can be applied to more general cases. Standing wave in stationary medium. Standing waves commonly arise when a boundary blocks further propagation of the wave, thus causing wave reflection, and therefore introducing a counter-propagating wave.
Waves exhibit common behaviors under a number of standard situations, e. Absorption of waves means, if a kind of wave strikes a matter, it will be absorbed by the matter. When a wave with that same natural frequency impinges upon an atom, then the electrons of that atom will be set into vibrational motion. If a wave of a given frequency strikes a material with electrons having the same vibrational frequencies, then those electrons will absorb the energy of the wave and transform it into vibrational motion. Refraction is the phenomenon of a wave changing its speed.