cherenkov radiation?
In: Physics
I’m going to try.
Drag your hand across some water quickly. You will see the ripples from it are in a cone pointing the direction of where your hand is going. By the time the ripple reaches someone your hand is no longer where it was when it created that ripple. If it’s fast enough the water turns into a splash. You are hitting it faster than the speed of water. Faster than it can get out if the way.
When a jet flies really fast it produces a cone of sound. But once it reaches the speed of sound the air can’t get out of the way fast enough and it creates a sonic boom.
A radioactive material gives off charged particles like electrons and they fly away very fast. Typically slower than the speed of light. But, light travels more slowly in something like water. It slows the light enough that when the particle goes through the water it excites other particles and gives them enough energy to glow. Sensors can see the cone like the ripples in the water and see how fast it is and what direction it is going.
Check out this podcast episode.
https://player.fm/series/daniel-and-jorge-explain-the-universe-2445537/can-you-slow-down-light
Think of a particle of radiation like a jetski with two passengers. The jetski is buzzing along as fast as it can on a lake and everything’s fine. But then it moves from the lake to another medium – dry land – where it can’t go as fast. The moment it hits the dry land it’s forced to go slower, and as a result it releases some of the energy, in the form of the passenger. Your girlfriend flying off the jetski when it hits dry land is like the particle of radiation releasing a photon when it moves from water to the air.
Electrodynamic rule is speed of light in vacuum would always be c, independent of any inertial frames.
However speed of light in other Dielectric mediums having refractive index >1 would be less than c.
for example light travels at .75c speed in water..slower than speed in vacuum.
Therefore in such medium where light is traveling at slower speed while matter can be accelerated greater than speed of light in same medium and obviously less than speed c…we can create same condition of sonic boom of sound waves.
Light photons emitted from electron traveling in medium cannot escape as electron is traveling faster than photon …so it continues to build wavefront same like in sonic boom and pure coherent energy is released having photon in same phase velocity.
Due to high energy release..higher frequency photons are released which is of low wavelength…hence blue or violet light is visible as form of cherenkov radiation.
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