Light OR Sound? - Unraveling the Mystery

AI Thread Summary
Clapping produces sound waves due to the vibration of air molecules, creating pressure waves that we perceive as sound. In contrast, lighting a torch does not produce sound waves because it involves the emission of photons when electrons transition between energy states. The distinction between light and sound lies in their physical properties; light is a quantum mechanical phenomenon while sound is macroscopic. Intuition plays a limited role in predicting whether light or sound will be produced, as individual perceptions vary. Understanding the underlying physical processes helps in making informed guesses about different scenarios involving sound and light.
Blade_Runner
Messages
8
Reaction score
0
Light OR Sound!

When we clap, we hear a sound..The reason is that on clapping sound waves are produced...
My question here is why?
Why Does Clapping produce a sound wave and not a light wave...Or when we light a torch, why are sound waves not produced...
Also, When a electron jumps from conduction band to the valence band, light is produced...What is the reason for this...
How do we decide by our intution whether light or sound would be produced...
 
Science news on Phys.org


Sound is produced by the vibration of the molecules of a medium, such as air. So clapping your hands creates a pressure wave which propagates and we experience this in sound. As you appear to know, photons are emitted from energy state transitions. The jumping electron, in the case you mentioned, releases a photon because it moves from a higher to a lower energy state, and the conservation of energy states that the extra energy must go somewhere, so it is released in the form of a photon.

In sum, light is a quantum mechanical property while sound is macroscopic.
 


Lighting a torch most certainly does produce sound. They are entirely separate processes which are not mutually exclusive.
 


How do we decide by our intution whether light or sound would be produced...

We don't rely soley on intuition because your "intuition" and mine are likely quite different. Also your visual acuity and hearing might be quite different and could affect your perception of what's going on. Actual production sound vs light of course is a different matter.

But by having a basic idea of the physical processes involved in the production of each, described above, you can make some informed guesses about, for example, slapping an oar on water; bubbles emerging in boiling water, radium decay, observing effects of a thunderstorm.
 
Thread 'A quartet of epi-illumination methods'
Well, it took almost 20 years (!!!), but I finally obtained a set of epi-phase microscope objectives (Zeiss). The principles of epi-phase contrast is nearly identical to transillumination phase contrast, but the phase ring is a 1/8 wave retarder rather than a 1/4 wave retarder (because with epi-illumination, the light passes through the ring twice). This method was popular only for a very short period of time before epi-DIC (differential interference contrast) became widely available. So...
I am currently undertaking a research internship where I am modelling the heating of silicon wafers with a 515 nm femtosecond laser. In order to increase the absorption of the laser into the oxide layer on top of the wafer it was suggested we use gold nanoparticles. I was tasked with modelling the optical properties of a 5nm gold nanoparticle, in particular the absorption cross section, using COMSOL Multiphysics. My model seems to be getting correct values for the absorption coefficient and...
Back
Top