TheCorridorTheories

Nuclear Power

2012-08-10T16:20:00.000-07:00

Statistically, nuclear energy is the safest form of power generation. Unfortunately, thanks to the media, most people are afraid to power a kettle with it.

Pro coding skill

2012-08-10T14:35:00.001-07:00

If you're at a programming class, or some place with a laptop and you have no idea what you're doing, and you don't want to appear lost, check hackertyper dot com out!

#You must have internet access, obviously.

The site speaks for itself.

Green Energy?

2012-07-31T10:27:00.002-07:00

Modern technology has significantly improved our lives. You can see the mark of engineers everywhere around you: be it the ceiling fan or the monitor that you're staring on, humans have indeed come quite a long way.

Unfortunately, everything around us is terribly reliant on energy. Conservation of energy literally makes our clock tick, and powers our lives. Therefore, losing all our energy sources is indeed an unpleasant thought. Human scientists are working around the clock to use green energy in fueling our hunger for power - however green energy isn't as efficient as those you get from nonrenewable sources...

What is green energy, you might ask?

That is the point of this post - to lay the groundwork for an upcoming green energy post that I've been working on for quite a while. Without further ado:

I'm here to tackle all your questions on renewable energy, if you have them. Leave your questions below.

[citation needed]

2012-07-14T09:03:00.000-07:00

The posts on this site are usually of good quality, meaning I do some research regarding the topic before I write anything. I would never write something that is just based on rumors, or worse, something that does not exist.

*shudder*

What I'm trying to say is that I don't think I'll be able to provide sources for every post I do, sources like what you might see in a thesis. If I were to do that... it'll take up a lot of my time :(.
The sources/citation links would also present themselves as whole new unnecessary blocks of text.

Which is what this website is trying to avoid.

I try to make physics, or physics concepts easily understandable by the average reader. I can't do that if I were to show you every source to every science 'fact' that is mentioned in every post. Worst case scenario, the readers will feel the burden of knowledge and not read what I have to say entirely.

Yes, I can't deny that you should take everything posted here with a grain of salt. Although, I assure you, that every post I make is of the utmost quality. I have countless posts that were scrapped and remain in my blogger.com draft graveyard.

I have a post regarding 'Intrusive Thoughts' that I've been working on for weeks, but due to my own limitations I have never felt that it was up to standard, and it sits nicely on top of all the other drafts.

Someday, perhaps.

Triboluminescense

2012-07-09T02:40:00.001-07:00

Triboluminescence is a physical process through which light is generated when materials are crushed, rubbed, and ripped - as electrical charges are separated and reunited. The resultant electrical discharge ionises the nearby air, triggering flashes of light.

Commonly known as 'Smash Glow Crystals', the triboluminescent property of certain materials has always intrigued the masses on the internet.

Google those phrases, watch the videos, and prepare to be mesmerised.

Further reading:

The spectrum of light produced by (sugar) triboluminescence is the same as that for lightning. In both cases, electrical energy excites nitrogen molecules in the air. Most of the light emitted by nitrogen in the air is in the ultraviolet range that our eyes cannot see, and only a small fraction is emitted in the visible range. When the sugar crystals are stressed, positive and negative charges accumulate, finally causing electrons to jump across a crystal fracture and excite electrons in the nitrogen molecules.

Different triboluminesence light have different spectra. The duct tape videos that you see on the Internet mostly emit light in the form of X-rays. In some cases, they could be strong enough to create an x-ray image!

Sugar triboluminescence was one of the first known scientific occurrence of tri-(this word is really hard to spell).

Ancient Nuclear Reactor

2012-07-03T05:22:00.001-07:00

In 1972, the French Physicist Francis Perrin discovered that nature had created the world's first nuclear reactor two billion years before mankind.

This natural reactor formed when a uranium-rich mineral deposit came in contact with groundwater, which slowed the neutrons (particles) ejected from the uranium so that they could interact with and split other atoms. Heat was produced, turning the water to steam, thus temporarily slowing the chain reaction. The environment cooled, water returned, and the process repeated.

TL;DR - Nature made a nuclear reactor way before the Manhattan project was even conceived

The Crossbow

2012-06-22T11:02:00.002-07:00

Through the centuries, the crossbow was a weapon that employed the laws of physics to wreak military havoc and pierce armour. The crossbow changed the odds of battle triumphs in war during the Middle Ages. One of the prime reliable records of this weapon in use in war dates to the battle of Ma-Ling in China, but even older crossbows have been found in Chinese tombs.

Early crossbows generally were bows mounted to sticks of wood, or 'wooden tillers/stocks'. The short, heavy, arrow-like projectile called a crossbow bolt traveled along a groove through the tiller. As the crossbow evolved, various mechanisms were used to pull back the string and then hold the string in place until it was ready to be fired. Early crossbows had stirrups for holding an archer's foot (maintaining a strong position) as he pulled back the strong with both hands or a hook.

Physics improved these killing tools in several way. A traditional bow and arrow required that the archer be full of strength to draw the bow and hold it steady while aiming. However, with crossbows, a weaker person could use his leg muscles to assist drawing the string. Later, various levers, gears, pulleys, and cranks were used to amplify the user's strength when pulling back the string. In the fourteenth century, European crossbows were made of steel and employed crannequins - a toothed gear attached to a crank. An archer would then turn the crank to pull the bowstring.

The penetrating power of a crossbow and ordinary bow comes from energy stored when bending the bow. Like a spring that is pulled and held, energy is stored in the elastic potential energy of the bow. When released the potential energy is converted into the kinetic energy of movement.

Are you as smart (or as bad) as you think you are?

2012-06-16T05:39:00.002-07:00

This topic really hits close to home. I've been searching through the web for articles or feedback relating to intelligence and perseverance, and I stumbled upon a few MIT graduates who certainly had something to say -

Inri137's comment

eigenfunc's response:
Thank you for writing this. As a recent MIT grad, this really resonated with me, since I came to very similar conclusions over the last few years.
When I first started MIT, I stood in awe of fellow freshmen who were taking 8 classes a semester and getting ready to do graduate work in math and physics. And I rambled on to my parents and whoever would listen about how unfathomably smart these kids must be. I was obsessed with this idea of the genius MIT student that I clearly wasn't.
My dad told me something that I wasn't able to appreciate until much later --- that it's not about being "smart", but about sustained focus, dedication, and discipline. I didn't believe him. I figured that some people are just born smarter, and there's an upper limit on your intelligence that holds you back, and that I had hit that limit. No doubt some people are more predisposed to certain kinds of achievement. It's very very easy to blame your intelligence than your motivation when by all accounts, you are busting your ass, killing yourself spending 20 hours on each analysis problem set and those guys are spending less than 5.
But then I started thinking about those kids I idolized. Some of them had been doing programming or math competitions since they were in elementary school. One of my friends would tell me things like "I'm thinking of going through a complex analysis book this summer and going back through my notes to review my topology." Now this was a guy with /focus/ and /dedication/! I thought to myself: until I spend that much time doing focused work, how can I expect to be as good?
I realized that "genius" is overrated. It is rarely just there. You have to focus and keep pushing yourself to get there.

These thoughts had confirmed what I suspected all along. It's not about being clever, but it's about your commitment, your dedication and self-discipline. No one is born smarter, no matter what people seem to look like from your perspective. I've blamed my own intelligence than my motivation similar to the post above when in fact, I've just not been working hard enough.

I really hope someone reads this and gets the message.

The best way to learn how to learn is to push yourself into situations where you aren't the smartest person in the room, and to observe and get help from the people who are the smartest, to find out how they do it.

TL;DR-
"Smart" is really just a way of saying "has invested so much time and sweat that you make it look effortless."

True End.

2012-05-30T01:51:00.002-07:00

Garfield is actually dieing of starvation, and just imagining Jon and Odie. There was a reference to this in a Halloween themed comic. Garfield woke up in a condemned and abandoned house. He calls out for Odie and Jon, but there is no answer. He then wills the illusion back on himself, and continues his delusions about his 'family'.

Now go back and highlight the blank space before the above comic, right below the title.

Read the last panel of the comic.

Have a good day.

Science.

2012-05-14T03:28:00.003-07:00

"As the island of knowledge grows, the surface that makes contact with mystery expands. When major theories are overturned, what we thought was certain knowledge gives way, and knowledge touches upon mystery differently. This newly uncovered mystery may be humbling and unsettling, but it is at the cost of truth. Creative scientists, philosophers and poets thrive at this shoreline."

- W. Mark Richardson, "A Skeptic's Sense of Wonder"

All water on Earth put together in a single ball

2012-05-04T23:46:00.001-07:00

The picture below illustrates the size of a sphere that contains all the water on Earth, in comparison to the Earth itself. The blue sphere sitting on top of the United States has a diameter of about 1,385 kilometres, with a volume of a colossal 1,386,000,000 cubic kilometres. The ball of water includes all of the water from the oceans, seas, lakes, rivers, icebergs as well as groundwater, water in the atmosphere, even the water in living beings, humans, animals and everything in your garden.

Source: http://ga.water.usgs.gov/edu/2010/gallery/global-water-volume.html

Credit: Illustration by Jack Cook, Woods Hole Oceanographic Institution; USGS..
Data source: Igor Shiklomanov's chapter "World fresh water resources" in Peter H. Gleick (editor), 1993, Water in Crisis: A Guide to the World's Fresh Water Resources (Oxford University Press, New York).

Disclaimer: I do not own anything in this post. All rights belong to the people linked above.

Smartphones with X-ray Vision?

2012-04-23T17:08:00.004-07:00

Four days ago, on the 20th of April, the University of Texas announced to the world that they have created a technology that will give smartphones the ability to see through walls, through the application of T-rays.
Of course, we know that cameras with see-through capability have been around for quite some time. Existing cameras with 'penetrating vision' detect infrared radiation which goes through cotton-based clothing.

So what does the aforementioned technology bring to the table?

Imagine the infrared technology we already have, vastly improved, minaturised and produced cheaply enough to make it usable for the everyday consumer, where it can help detect skin cancer and cracks through walls.

Read more:
Article 1
Article 2
Article 3

"CMOS is affordable and can be used to make lots of chips,” Dr. O said. “The combination of CMOS and terahertz means you could put this chip and receiver on the back of a cellphone, turning it into a device carried in your pocket that can see through objects

To answer lingering questions in your mind:
1. What exactly are T-rays?

T-rays were discovered way back in the 1960s, and were pushed to the forefront of the scientific page in 2005. Terahertz radiation(T-rays) refers to electromagnetic waves propagating at frequencies between the infrared band and the microwave bend. Technically, they can still be classified as infrared rays.

Terahertz waves can pass through everything sans metal and water. It's usefulness as a communication tool is severely limited by it's relatively short range, since Earth's atmosphere absorbs most of it.

2. So... smartphones with X-ray vision, where can I get one?

As a matter of fact, the application of terahertz radiation is pretty common. This CMOS + T-rays combination is still new, and there will definitely be some kinks to iron out before the corporate world can commercialise the technology.

3. Can I use this to spy on peop- I mean, isn't this an invasion of privacy?

It could be. The researchers at the University of Texas claim that for privacy reasons, their research will only focus on a maximum length of 10 centimeters. Terahertz radiation itself has a very short range, but with the CMOS detectors, who knows?
The only thing that I can safely say (for now), is that there is no chance of you sneaking up on someone and... you know.

What do you mean, this isn't the Tray you're looking for?

Edit: Apparently people are only concerned about 'can it see through clothes?' Technically, yes, but the resultant images aren't viable for privacy invasion issues.

The Hardest Logic Puzzle in the World

2012-04-10T02:25:00.001-07:00

Blue Eyes:
The Hardest Logic Puzzle in the World
A group of people with assorted eye colors live on an island. They are all perfect logicians -- if a conclusion can be logically deduced, they will do it instantly. No one knows the color of their eyes. Every night at midnight, a ferry stops at the island. Any islanders who have figured out the color of their own eyes then leave the island, and the rest stay. Everyone can see everyone else at all times and keeps a count of the number of people they see with each eye color (excluding themselves), but they cannot otherwise communicate. Everyone on the island knows all the rules in this paragraph.

On this island there are 100 blue-eyed people, 100 brown-eyed people, and the Guru (she happens to have green eyes). So any given blue-eyed person can see 100 people with brown eyes and 99 people with blue eyes (and one with green), but that does not tell him his own eye color; as far as he knows the totals could be 101 brown and 99 blue. Or 100 brown, 99 blue, and he could have red eyes.

The Guru is allowed to speak once (let's say at noon), on one day in all their endless years on the island. Standing before the islanders, she says the following:

"I can see someone who has blue eyes."

Who leaves the island, and on what night?

There are no mirrors or reflecting surfaces, nothing dumb. It is not a trick question, and the answer is logical. It doesn't depend on tricky wording or anyone lying or guessing, and it doesn't involve people doing something silly like creating a sign language or doing genetics. The Guru is not making eye contact with anyone in particular; she's simply saying "I count at least one blue-eyed person on this island who isn't me."

And lastly, the answer is not "no one leaves."

I've done my best to make the wording as precise and unambiguious as possible (after working through the explanation with many people), but if you're confused about anything, please let me know. A word of warning: The answer is not simple. This is an exercise in serious logic, not a lateral thinking riddle. There is not a quick-and-easy answer, and really understanding it takes some effort.

Source: xkcd.

Stuff to read.

2012-03-26T08:35:00.001-07:00

http://io9.com/5623112/the-smell-of-freshly+cut-grass-is-actually-a-plant-distress-call

Filler Post

2012-03-18T10:14:00.000-07:00

I blame Golden Sun: The Lost Age for my love for video game soundtracks.

And Pokemon. Mainly Pokemon Silver. I spend endless hours covering video game tunes on my guitar/fiddle/whatever close to me when the mood strikes.

None of which are of presentable quality, of course. (my covers)

Oh, Blazblue and Guilty Gear are the main perpetrators of my liking towards melodic soloes.

Not many people listen to video game music. Pop music dominates over the young generation. I like pop music too, but I also like my gaim musics, which is, sadly not the case for many other people.

If you want someone else to listen to video game music, just throw Bastion at them. Should work out fine.

Speaking of which, Megaman X - Maverick Rising is the album i'm listening to right now, and I must say, it really is quality material.

What does this have to do with Physics? Nothing whatsoever, I'm just mulling over what music to listen to while i begin reading 'The Infinity Puzzle' by Frank Close. It just arrived in the mail today.

Will probably share what I read. Cheers.

Lynas: What it actually means to the citizens of Malaysia

2012-03-01T21:48:00.000-08:00

LynasCorp had recently set up a rare-earths processing plant in the country of Malaysia. This was met with unfavourable reactions. Certain influential people are using this to their advantage to gain trust and power in the wheel of politics. The real problem with this Lynas issue, however, is how the 'people in charge' are handling the issue.

First things first, as a science student, I had done some research on the hazards of this chemical plant. Surprisingly, the chemical plant is perfectly safe. (I'll get to that point later)

What's wrong with Lynas, however, are these:

The decision to allow the plant to be built way back in 2008 without a public revelation
Tax Exemption for 12 years. 12 years? Seriously? This is a radioactive material industrial plant worth billions of dollars. Why are we so kind?
The Fine if anything goes wrong (RM50 mil.) is definitely too low compared to their profits (RM 8 bil. per year)

And these:

The surrounding area's estate worth will experience a significant drop.
Foreign investors might think twice due to the presence of radioactive waste threat. (disputable, but nobody expects the investors to have engineering/science degrees)

Now that the nasty stuff is out of the way, lets take a closer look at the current state of argument. The youth of Malaysia are sadly misinformed by the hazards of the chemical plant (I blame Facebook and 9gag).

Most of them wish for the plant to be taken down an-

EDIT: This website/article explains everything that was here previously, only in a more solid fashion. Check it out. http://mynewshub.my/eng/2012/02/the-truth-about-lynas/

Sigh.

My point being, we shouldn't rush to join the mob just because of some text and a few rage images. Read about the problem, check the validity of the sources before making any decision.

I welcome any comments on this matter.

TL;DR: The chemical plant is fine. (as long as they follow the standards set by Malaysia)

Substituting electrons with photons

2012-02-26T04:58:00.001-08:00

It has been quite a while since the last post. Here's something directly from the labs of the University of Pennsylvania:

First Physical 'Metatronic' Circuit Created

The technological world of the 21st century owes a tremendous amount to advances in electrical engineering, specifically, the ability to finely control the flow of electrical charges using increasingly small and complicated circuits. And while those electrical advances continue to race ahead, researchers at the University of Pennsylvania are pushing circuitry forward in a different way, by replacing electricity with light.

Original

This discovery, or rather, technology has huge implications. Light travels a million times faster than electricity (exaggeration. don't quote the math), but that's not the major thing here. Electronic circuits are limited by orientation of poles, and the nature of electrons themselves. If light is used to replace them, infinite numbers of circuits can be created. There will be myriad options, more complex circuits can be created to perform tasks that would otherwise be impossible with the current electronic circuits.

The field of Electrical and Electronics Engineering has just undergone a paradigm shift- There are so much more to discover.

MAKE A LASER -FINALES FUNKELN-

2012-02-03T22:51:00.000-08:00

harvest a bunch of LEDs from DVD drives

buy a collimating prism

make a superpowerful superlaser

profit?

I'm really tempted to try making a superlaser myself. I have the knowledge to do so. Unfortunately I don't have a bunch of DVD drives lying around my place.

Nor do I know where do I purchase a collimating prism. I could make one myself, but I can't seem to get the glassy texture right.

MAKE A LASER!
YES
NO

Semi-related:

My take on quantum healing

2012-01-18T01:03:00.000-08:00

So I've been receiving messages asking my opinions of quantum healing. Quantum healing is a belief that are based on a scientific level that there are things that happen on the microscopic scale that we can't fully explain.

The world inside an atom is a strange place where things don't behave like they do in the macroscopic world. Particles behave bizzarely, waves behave like particles, particles behave like waves.

Particles in the universe are always in communication with each other. This is a true physics fact and is used as the basics of quantum mysticism, eg: quantum healing, The Secret, and so on...

Some of you might be familiar with the Pauli Exclusion Principle. No electrons can occupy the same energy level. This means that each and every electron in the universe must not share the same energy level. This brings us to an amazing hypothesis: Every action that you do has a resounding effect throughout the universe.

An action will definitely involve the movement/motion of electrons. The electrons shift and jump, changing energy levels. However, as the Pauli Exclusion Principle states, every electron in the universe will respect the changes in the aforementioned electrons by changing theirs, effectively impacting the universe.

Everything is connected to everything else.

If the above is true and proven, then what is the scientific argument that disproves quantum mysticism?

Quantum theory doesn't just apply to subatomic particles, it also applies to you and me. Why don't we see the effects? The reason is due to the smallness of Planck's constant (which was discovered by coincidence).

An example: Say you want to 'teleport' out of a closed room. Before you scoff at the idea, let me remind you that quantum theory can show you that the above scenario is theoretically possible. Feynman's path integral (a physics formula) displays the probability for said teleportation to occur.

The equation for Feynman's path integral (which takes all the probable paths a particle takes through the universe), heavily simplified is represented as follows.

MSPaint to the rescue.

t = time you have to wait to have a reasonable chance to teleport to your destination
x= distance you want to travel
^x = length of the room
m = your mass

h = Planck's Constant.

In this example we let x be 3m, ^x be 2.5m and m be 60kg.

I hope you have a calculator handy because I'm not displaying the calculations here.

...

...And we get... t = 6.9 x 10^35 seconds
(correct me if I'm wrong)

In years, that would be 2.18652476 × 10²⁸ years

Which is... let me put that into perspective. The current age of the universe is 13.7 ± 0.13 billion years. (x10^9)

So yes, there are strange stuff in quantum theory but there's absolutely no chance we'd get to apply them in our day to day lives.

TL;DR = Quantum Healing probably doesn't work due to the fact that quantum effects are only observable on the microscopic scale.

The life of a labourer with Physics

2012-01-12T10:08:00.000-08:00

As some of you might know, I currently work as a construction labourer, saving up to be able to afford the Bachelor of Science (Physics) courses. The work is very taxing on the body, but the mind is not affected much.

While working, I occasionally think of the physics principles involved in whatever I'm doing right now, say I'm demolishing a wall. Naturally, Newton's Third Law of Motion floats around in the back of my head whenever I'm using the rotary hammer (a type of jackhammer), and how it makes my arms sore. Much of the reaction force is mitigated by the weight of the hammer itself, but the concept backfires when you have to pound locations higher than you.

I was having a rough time shoveling sand, thinking about the shovel being a Class 3 lever, when I realise I've also been unconsciously working the shovel using the couple mechanic. I had my left hand pull the shovel up, while my right hand pushes down on the handle.

A poorly-drawn shovel

A couple is a system of forces with a resultant torque but no resultant force (obligatory physics definition)

Green Arrow : Force that left hand applied
Pink Arrow: Force applied by the right hand
Black Dot: Centre of rotation.

Get the picture? (no pun intended)

These thoughts made me realise how much I enjoy physics, and how good it would be to have a physics degree.

P.S. What is it with Physics students/teachers and their lousy drawings?

A Night with the Stars

2012-01-09T09:45:00.000-08:00

Here's some really interesting knowledge to relax your mind after the constant wave of X-ray postings:

If you didn't know Pr. Brian Cox before this, you do know. Professor Brian Cox is a British physicis- I think I should leave that to wikipedia. Read his wikipedia entry to know the nitty-gritty stuff!

In general, he's a pretty awesome person. A rockstar physicist.

Anyway.

I implore you to watch this video, not only for the sake of knowledge, but the video is very entertaining and explains the basics of quantum physics (Quantum Theory) in great detail. Recorded meticulously by the wonderful people over at the BBC at the Royal Institution of Great Britain, Pr. Cox brings us mundane people to the wonderful world of particle physics, in just one hour. You'll be wishing that the video lasts forever by the time you're done.

Pr. Brian Cox - A Night with the Stars.

Did you think physics was nerdy? Well, you thought wrong.

Characteristic Line Spectrum

2011-12-24T05:47:00.000-08:00

Also previously known as the 'K and L in the graph'.

Previously, we were left with this 'hanging' piece of information:

The characteristic X-ray spectrum which consists of sharp peaks of high intensity occurs at specific wavelengths, unaffected by the voltage of the X-ray tube.

The peaks are a result of the electrons from the cathode knocking out inner shell electrons from the target atoms. When the vacant shells are refilled by free electrons, X-ray photons of specific wavelengths are emitted.

Include the two MSpaint sketches of the mechanism behind the characteristic X-ray spectrum here.

The K and L in the previous graph each stand for their characteristic line series peaks respectively.

The K-series peaks consist of Ka and Kb. (assuming Ka = Kalpha and Kb= Kbeta for the sake of convenient typing/editing) These peaks occur when the innermost shell, the K-shell, is refilled by electrons from the outer shells. As a result, X-ray photons corresponding to the series are emitted. The figure above displays the transition responsible of the K-series peaks.

Similarly, The L-series peaks consist of La and Lb, and they occur when the second shell, the L-shell, is refilled by electrons from the outer shells.

The peaks are unique for each target element. In fact, an element can be identified from the peaks.

X-Ray Spectra!

2011-12-13T02:03:00.000-08:00

This post will either be boring or extremely fascinating, depending on whatever floats your boat.

The minimum wavelength of an x-ray occurs when all the energy of the accelerated electron is converted into an X-ray photon in a single collision. However, most of the accelerated electrons are stopped after a few collisions. Different electrons convert different amount of their kinetic energies into X-ray photons of different wavelengths, resulting in the continuous background spectrum.

Using an X-ray spectrometer and a crystal as a wavelength selector, the intensity of X-rays emitted as a function of its wavelength can be measured and then plotted.

The X-ray spectrum.

The X-ray spectrum consists of a continuous background of X-ray radiation and a series of characteristic lines with intensity peaks.

In the continuous background, the intensity varies smoothly with wavelength. The background intensity reaches a maximum value as the wavelength increases and then falls as the wavelength increases further.

The characteristic X-ray spectrum which consists of sharp peaks of high intensity occurs at specific wavelengths, unaffected by the voltage of the X-ray tube.

The peaks are a result of the electrons from the cathode knocking out inner shell electrons from the target atoms. When the vacant shells are refilled by free electrons, X-ray photons of specific wavelengths are emitted.

Witness my awesome paint skills.

Painstakingly painted in MS Paint.

The figures above show the mechanism behind the characteristic X-ray spectrum.

What's the K and L in the Graph? What do they stand for?

Until next time.

X-RAYS -genesis-

2011-12-09T17:11:00.000-08:00

X-rays play a very important role in many fields, especially in medicine. X-ray images of internal organs are used extensively in medicine as a diagnostic tool. An X-ray technique called computer-assisted tomography (CAT) enables a clearer view of the structure of any part of the body without any need for surgery.

X-rays are a form of electromagnetic radiation. The wavelength of X-rays are in the range of .01 to 10 nanometers. Shorter than UV rays, longer than gamma rays. X-rays are also classified into two classes, 'soft' x-rays and 'hard' x-rays respectively.

Needless to say, hard x-rays have greater penetrating power. That's the only major distinguishing factor.

So...

X-rays. What do you know about them? Nothing? How are they produced?

We're going to paint a basic picture about the production of x-rays.

Literally.

Electrons are emitted through thermionic emissions when the filament is heated by current flowing in it. The electrons are accelerated towards the copper anode by the high potential difference ranging from 10^4 V to 10^6 V between the anode and the cathode.

The glass tube is evacuated so that the electrons are pulled towards the anode at a very high speed without colliding with air molecules.

The electrons decelerate rapidly on impact with the target. As a result, some of the kinetic energy is converted into X-rays. Less than 1% of the total energy supplied to the X-ray tube is converted into X-rays, the remainder is released as heat.

So inefficient.

The target metal must be made of heavy metals with a high melting point such as molybdenum or tungsten, to prevent the target from melting easily.

X-rays of short wavelength and high penetrating power are called HARD X-rays. X-rays of long wavelength and low penetrating power are called SOFT X-rays.

Minimum wavelength, λmin = hc/eV

Laser -Degree-

2011-12-03T22:18:00.000-08:00

Stimulated Emission

Previously in our online 'course', we discussed about the basic principle of the laser technology. With the limited information provided, surely you must have come to a conclusion that stimulated emission is simply not sustainable without sufficient excited atoms.

And you may also have deduced that to achieve the required number of excited atoms is pretty complicated.

This is where population inversion comes into play.

See, in lasers, light emission by stimulated emission occurs more than by spontaneous emission. To achieve this state, the number of atoms at high-energy levels must exceed the number of atoms at ground state.

This situation is known as population inversion. To make population state possible, a state called metastable state is created. In the metastable state, the atom remains in the excited state a little longer than usual.

Which brings us to an example:

The Helium-Neon Laser.

A mixture of helium and neon gas in the ratio of 20:80 is contained in a tube with mirrors at both end. When a potential difference (Voltage) is applied across the tube, electrons will travel along it.

Refer to the below diagram if you aren't a university graduate who probably should already know all this stuff.

Laser technology is taught even in the very basic of physics university courses.

Electrons colliding with the helium atoms cause them to be raised to energy level E2 (20.61eV). This value is close to the energy level of neon E4(20.66eV).

Collisions between the helium and neon atoms enables the neon atoms to attain energy level E4 easily, hence, the number of neon atoms at E4 is more than the number of neon atoms at E1.

And we have a Population Inversion.

Which brings us back to our previous course:

http://thecorridortheory.blogspot.com/2011/12/laser.html

The combination of all of this results in a highly coherent, intense beam of light.