Skip to main content

Quanta of light

Light, also known as visible light, is simply a small fraction of the electromagnetic waves spectrum generated by every particle. What this means is that light are simply particles/waves, more on this later, right now we'll just consider them as particles of photons. vibrating at a certain frequency that our eyes can pick up as visual signals to send to our brain. In this case these particles would be the photons. A typical human eye will respond to wavelengths from about 390 to 700 nm. These values would mean different colors to us. So yes a designer's concept of colors can be in #00FF00 or #0000FF also known as hex color codes, but in a scientific point (physics rather) colors are just caused by how our eye pick up photons vibrating at different wavelengths. 390nm would be violet while it gradually scales to where 700nm would be red. It is often theorized that different animal/insects can perceive a wider range of wavelengths as light and thus are able to see colors unknown to mankind. Pretty amazing.

These lights obviously have different energy levels as shown by their wavelengths red has the least energy while violet has the highest. A shorter wavelength is associated with a higher energy level EM wave since it 'vibrates' more frequent. Therefore if it gets any shorter it becomes what we call Ultraviolet light, invisible to the naked eye, but still detectable in certain situations. Scaling it up we would get X-rays and Gamma rays.

One key factor that is highly discussed in the scientific field is the distinction of ionizing radiation and non-ionizing radiation. To laymen, this would be 'what kind of waves causes cancer?' This boundary is drawn somewhere along the higher-energy part of ultraviolet waves. Any higher energy waves if exposed without protection would cause ionizing of molecules in your body, resulting in damaged cells and thus cancer. This is also why visible light don't cause cancer. Microwaves and radio-waves are at a energy level even LOWER than visible light, so don't worry about microwaved food causing cancer or that your microwave is leaking waves. Yes they heat things up, and so do light. Heating things up and breaking apart your cell molecules are two very different things.

Gamma rays for example, are one of the key constituents released in a nuclear bomb, and as you would expect, they are ionizing as f**k. In fact, these waves are so strong that anyone in close proximity of the explosion won't feel any pain because there is nothing left to feel pain. Nearly every cell in your body is broken almost instantly and NOTHING works.

Regarding the issue about light being a wave OR a particle, after many years scientists have decided that it is simply both. This is known as wave-particle duality. That means that under certain scenarios we would classify light as particles and sometimes waves. This is due to several phenomena in quantum mechanics that we wouldn't go through in this post as they are rather complicated. However, one video on youtube sums this up quite nicely.

Simply put, particles are solid objects (imagine a very very small ball) and waves are anything that travels in a wave pattern (imagine ocean waves, sound waves).
If you throw that said very small ball, it would travel in a straight line. If you shoot out that said wave, it would spread out into a wave pattern. This can evidently be seen by daily speech, when you make a sound, everyone AROUND you can hear it, not just a fixed line of sound trajectory.

Since we say that light are both waves and particles, that would mean sometimes light moves as a wave, but if we try to track the individual photon's movement, it would behave as a particle. This is what we refer to as 'under observation' in subsequent posts.

There we have it, that is light.




Comments

Popular posts from this blog

Pair production and the second law of thermodynamics

There are a few postulates I would like to discuss here. They may or may not be true since that's the point of this post. Background Firstly, from the second law of thermodynamics it is said that entropy of the universe must always increase with time. Any conversion of energy from one form to another will always result in an increased disarray since typically one form of energy is converted into many other form such as electrical energy being converted to heat, light, kinetic etc. Taking into consideration that entropy is the disarray of anything, let us now consider the mass-energy equivalence e = mc^2. A small amount of mass can produce unimaginably high amounts of energy. Where e is energy measured in joules, kg*(m/s^2), m in kg, c in m/s. For one kg of mass, it's energy equivalent is 1kg x 300,000,000m/s x 300,000,000m/s = 9x10^16joules. One ton of TNT in comparison yields 4.184 x 10^9 joules of explosive energy. From the entropic perspective, we can say that the TNT p...