Asked by violet
What does a wave carry?
All Answers 1
Answered by
GPT-5 mini
AI
Short answer: a wave carries energy and information (and usually momentum, sometimes angular momentum). It does not, in the idealized picture, carry the bulk of the medium with it — the medium’s particles typically oscillate about equilibrium.
More detail and examples
- Mechanical waves (strings, sound, most waves in solids/liquids): they transport energy and momentum through the medium. The medium’s particles execute oscillatory motion; energy and momentum are transmitted from one part of the medium to another. In fluids there can also be small net particle transport (e.g., Stokes drift in water waves), but the dominant transported quantity is energy.
- Electromagnetic waves (light, radio): they carry energy, linear momentum (so light can exert pressure) and angular momentum (spin and orbital). The local energy flux is given by the Poynting vector S = E × H; the momentum density is S/c^2 (in vacuum).
- Information/signals: waves transmit changes in amplitude/phase/frequency, so they carry information — for example, speech in sound waves or data in radio waves. The information propagation speed is associated with the group or signal velocity.
- Phase vs. group: energy and information are generally carried at the group (or signal) velocity, not the phase velocity of individual wave crests.
If you want, I can give formulas for energy flux in a specific wave (e.g., a wave on a string, sound intensity, or the Poynting vector for EM waves), or discuss special cases like mass transport by water waves. Which case interests you?
More detail and examples
- Mechanical waves (strings, sound, most waves in solids/liquids): they transport energy and momentum through the medium. The medium’s particles execute oscillatory motion; energy and momentum are transmitted from one part of the medium to another. In fluids there can also be small net particle transport (e.g., Stokes drift in water waves), but the dominant transported quantity is energy.
- Electromagnetic waves (light, radio): they carry energy, linear momentum (so light can exert pressure) and angular momentum (spin and orbital). The local energy flux is given by the Poynting vector S = E × H; the momentum density is S/c^2 (in vacuum).
- Information/signals: waves transmit changes in amplitude/phase/frequency, so they carry information — for example, speech in sound waves or data in radio waves. The information propagation speed is associated with the group or signal velocity.
- Phase vs. group: energy and information are generally carried at the group (or signal) velocity, not the phase velocity of individual wave crests.
If you want, I can give formulas for energy flux in a specific wave (e.g., a wave on a string, sound intensity, or the Poynting vector for EM waves), or discuss special cases like mass transport by water waves. Which case interests you?
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.