Physics treats wave as a disturbance caused in one or more fields. The values of the field oscillate in a repeated manner in stable equilibrium.
Mechanical and Electromagnetic waves are the common waves studied in physics. Wave is, in fact, the transport of energy without any transport of medium.
Waves, in general, are everywhere, it is to be identified using a medium to understand its characteristics. A wave is defined as the disturbance that traverses through a medium from one point to another.
The waveform when stretched from one end to another, it remains in the rest position. If the particle is moved during its rest position, it forms a wave and starts moving from one point to another.
The characteristics of the particle make it move either upwards or downwards, sometimes forwards or backwards. The movement of the wave in any direction is called the pulse.
A pulse is a single disturbance moving from one point to another point. If the wave is continuously moved back and forth, it causes a ripple in the medium and it is called as a Wave.
In physics, there are two types of waves observed and analysed. One is the Stationary Wave and the other is the Travelling Wave.
Stationary vs Travelling Waves
The main difference between a stationary wave and a travelling wave is, the stationary wave does not transport any energy while travelling wave has the property of transporting energy from one location to another.
Comparison Table Between Stationary Waves and Travelling Waves (in Tabular Form)
| Parameter of Comparison | Stationary Wave | Travelling Wave |
|---|---|---|
| Property of the Wave | Stationary Wave does not transport Energy. | Travelling waves transport energy. |
| Amplitude | Stationary waves oscillate with different amplitude. | Travelling waves travel with the same amplitude. |
| Phase Difference | The phase difference between two particles is between 0 to pi | The phase difference between two particles is 0 to 2pi |
| Wave Profile | Wave Profile consists of Loops. | Wave Profile consists of crests and troughs. |
| Formation | The stationary wave can be formed only at a particular frequency and wavelength. | Travelling wave can be formed at different frequency and wavelengths. |
What are Stationary Waves?
A stationary wave is that continuously oscillate in time but the peak amplitude does not move in space. In simpler words, a stationary wave is the one which moves vertically but not horizontally.
A stationary wave has two waves which have constant wavelength and amplitude. These two waves travel in the opposite direction.
While the waves are moving upward and downward nodes are formed. A node is a position where the wave stands for a particular period.
An antinode is the position of the wave when it oscillates or vibrates in the maximum amplitude. Stationary waves were observed by a scientist named Michael Faraday.
The phenomenon is understood where the medium moves in the opposite direction to the wave. The resulting interference causes the wave to remain stationary.
Stationary wave does not transport any energy. The common phenomenon discussed above is called resonance.
The medium in which the standing waves occur is called the resonator. As the amplitude remains the same for both the waves, the propagation of energy is nil.
The harmonics of the stationary wave depends on the medium if it is fixed or open. If the medium’s end is fixed then the wave shall be inverted once it reaches. If the medium is open, the wave automatically turns right side up. Once both the ends of the medium is fixed, it keeps oscillating and at certain frequency stationary wave is produced.
What are Travelling Waves?
Travelling wave is a wave with a disturbance which moves along a medium. It transports energy from one point to another point.
The travelling wave moves with constant speed. The wave is caused due to the movement of a particle which disturbs the next particle adjacent to it.
The displacement of the static particle from its equilibrium to movement causes the wave to move. The wave is observed to travel through a medium, where a crest is noticed moving from particle to particle.
The crest is naturally followed by a trough and the cycle continues. The distinct wave pattern observed is called the sine wave.
The sine wave shall persist until another wave of a different frequency is introduced in the medium. Such movements of waves from one location to another, transporting energy is called a travelling wave.
Travelling wave is formed when it is not confined to a givens space. As such, a travelling wave is formed and will be in motion for a very short period.
References
- https://yakari.polytechnique.fr/Django-pub/documents/matteo2004rp-1pp.pdf
- https://arxiv.org/pdf/0901.1026
- https://arxiv.org/pdf/patt-sol/9701007