This lecture note will make your life ten-fold easier in the scope of the problems it addresses. Consider it a talisman. I discovered this a couple of weeks ago when I was solving these problems for my own conceptual understanding. So I waited till I can completely enunciate the big picture. When I confirmed that its valid for all the following problems I made this note and sharing with you.
What happens when some UV falls on biological molecules? (or any kind) some of these molecules like the wooden pole absorb the energy and there still remains energy which they can emit as visible light. So the UV light kicks the molecules and the molecules in turn emit visible light. This implies that the UV wavelength that the molecules absorbed energy at are very small compared to the wavelength at which they emit visible light. This is always the case.
When we say some materials are fluorescent it means they absorbed higher energy and emitted lower energy radiations of colorful light.
But this has a great deal of application apart from its theoretical interest.
Take a chicken tikka stick. (you have seen them right? a few pieces of raw chicken is pierced into a stick)
Now ask yourself the question. How to get it minimally and maximally heated up by the fire from sun. If its minimally heated its winter and if its maximally heated its summer.
Now there are 3 primary parameters that influence the situation. One is called distance from the oven that sun is. Two any change that can be made to this distance is governed by two parameter. one when along a particular direction when we look at the oven how far it is? That distance can be changed a lot due to relative motion of earth and sun. Lets say therefore we will hold the chicken stick quite straight so it goes as straight as we stand on a given location on earth. Thats called a perpendicular in some poor mathematicians dictionary.
2. The object can be a large object, eg say something whose picture you are taking. But as explained above its not the energy of the object (or momentum) which is directly coming into the problem. That would be an added degree of concern if the object is moving with certain velocity, a reason why pictures are blurred. Because motion of objects introduces additional energy-time-momentum-position variables and their corresponding uncertainties. For the argument of the above problem one can imagine the large sized object, lets say a bird, is standing still on a tree while its picture is being taken. In that case if the wavelength of the light [few 100 nano meters = 1/10th of a micrometer] is used (eg in a digital-camera) the corresponding accuracy of the light will be less than micrometers. You can take a very sharp picture of the bird, which is lets say 6 inch long. But when you zoom in to a large degree, the inaccuracies will show up. [in this case how to see a micrometer level image? Is a computer sufficient to show us the uncertain edges of the pixels?] If the wavelength (here visible light) is so small, evidently by de-Broglie relationship, momentum or energy of such light is very large. But its not as large to disturb the feelings of the bird. The bird doesn’t have a problem with visible light, and such energy does not disturb its position or energy or any thing so to say. So while Quantum Mechanics is valid, we are accustomed to say this is a classical mechanics situation. To say QM is invalid is incorrect. To say QM is understood to be valid is a knowledgeable position.
A small primer on optical attributes of Light.
( — largely edited, 18-19 January 2014, originally from; Wednesday, March 27, 2013 at 3:58 pm UTC + 05:30 )
If you ever seem, to be caught up between: they say light always moves at the same speed-c, they keep on harping, why then, its energy so different; we have light of various energy and frequencies. One that are harmful, like x-ray or ultraviolet and one that are quite soft on us all. The answer is there are two kinds of speed, when it comes to vector emissions like light, one speed is on the plane of polarization, giving us the energy or frequency or intensity of light waves, and the other, the speed perpendicular to that plane, that is; the speed at which energy of light is transmitted across the galaxy, its this latter speed, which is slated to be known as speed-of-light (instead of, speed of light’s energy transmission vs speed that determines the energy value of light transmission) and always a constant known as c, whose value is unchanged, as long as a single quantum of light is considered and in vacuum.
Note that vector emission means there are 3 dimensions, in which this wave is created or propagated, light wave, its a plane + a perpendicular dimension to that plane. The plane is called plane of polarization which always contains two fields, Electric and Magnetic field, and the perpendicular dimension is the direction in which the energy of the light wave is propagated, therefore, gives the light-wave-speed; which are again of two definition, the physical or actual speed known as group velocity, and the virtual, conceptual speed of each wave train, known as phase velocity. This definition of phase and group velocity are always to occur; for any kind of waves and not just light wave. So, the light-wave-group-velocity (for a single quantum-of-light, called photon) is always c = 2.99 x 10 (8) meters/second, in vacuum.
In my case therefore you see, 0 publications in 2001. The year I joined my PhD, I was learning more about snow-fall, JC Peney and Bus rides. 2002 I have hardly 1 or 2, that was the year when in the later half I was given the privilege of being able to sign for science papers. The next year I am already acquainted quite a bit, so signing more than 1 paper a month is no irksome involvement. I already know what I am signing it for. 20 papers a year. Then it grows to 60 papers the next year, thats papers a month, my team of 400 was producing where I have a legit share of expert contributions, through weeks of data-collection, analysis and data-mining etc. (There would be papers where I won’t have legit share, .. ) The next year 2005-2006 was my peak, 70 papers, You can check my pictures from 05-06 (on f-b) and see how much I was involved in the literally tons of ways experimentalists contribute 😉 No kidding not everything is visible outside the vacuum pipe, its risky)
Then you can see I am gradually climbing down, but its hard enough to climb down faster because you already have a history. Becoming celebrity is a one way affair, no return. With years my direct contribution goes down but history has that which is yet to come and that shows up as bigger share in contribution. (Just like the electron’s history-of-all-path must contribute towards its momenta for future)
I think thats a good connection, like the electrons the Physicists are lost, they are picking on different things and survive and their history makes it bigger.
The correspondence Principle. This guy which gets talked a lot has a simpler form at times. Again this principle is a specific or corollary of O = A*B with the understanding that even if one of the variable say A can be insignificant it still depends on the sequence of other variables which decides how significant the total outcome would be. Therefore given that B can be significant enough to over ride A’s insignificance the outcome O can be significant. In other words an event might correspond from a scale of insignificance to a scale of significance. Often a scale of insignificance can be the micro or nano scale and the scale of significance is reached because it is not insignificant. So there is a bridge between two scales, one of insignificance and one of significance. One of micro and one that is not micro but lies close. In all totality this is the reason why Quantum Mechanical effects can be carried to the Classical scale and this is known as correspondence Principle.
We can see ourselves in mirror and take our mirror reflected selfie as a consequence of Fermat’s Principle, the topic of discussion of the blog.
In the last few weeks I am trying to understand why light traverses straight lines and why it refracts. The other day I saw a little mug floating inside a bucket full of water. Inside water any object would look shortened, a phenomena known as refraction. That’s because light rays would “bend” inside water (towards a direction where they have to take a shorter path) as their speed must reduce, given to the fact that in the same time in a rarer medium light would have traveled a longer distance in the exact same time, which is no longer possible due to the crowd of molecules and subatomic ghetto that it meets along its way.
Now it may also be related that light bends in a denser media compared to a rarer media because an additional rotational force is working. In other words, the definition of straight line has to change in the medium, that is of different density, because path of light is changing. Light is the guy who suffers the least when something tries to buzz it, because its inertial property of mass is zero. The curvature of light or the bending or deflection known as Refraction is thus a measure of the sideways force or energy.
Thus speed of light in different media is a measure of this bending or curvature and is known as Snail’s law ( — Pun intended, its actually; Snell’s Law — ) . Automatically when distance and time have to readjust, to produce an angle or bending, known as refraction ( — possible because distance and time can produce an angle if they are equivalents — ) the speed must also change.
All these are inter related. Light refracts and its speed changes, in relative change in density of media because there are rotational or non-inertial effects.
( — or additional energy is available, or a force is acting to bring a curvature in light’s path, perhaps the electromagnetic effects of the molecules? Its not only distance or time that are equivalents, read one article of mine “All You Need To Know About Relativity” to understand; how energy and time and distance and in short all Physical Variables are equivalents of each other — )
Liliana has a bag of marbles. The bag contains 18 black,
15 red, 11 blue, and 8 white marbles. Liliana randomly takes
a red marble from the bag and leaves the marble on a table.
What is the probability that she will next take a red or a white
marble from the bag?
1. A ball is thrown with an initial velocity of 20 m/s at an angle of 30°
above the horizontal. What is the instantaneous vertical velocity of
the ball when it is 5.1 m above the release point? (g = 9.8 m/s^2)
A. 0.2 m/s
B. 6.6 m/s
C. 10 m/s
D. 17 m/s
ପ୍ରଥମତଃ ସେ ଏକ ଆଇନ୍-ଷ୍ଟେଇନିଆନ୍ ବିଦ୍ଧି ରେ ଏବଂ ତା ପରେ ଏକ ସ୍ରୋଡିଂଜର୍ ବିଦ୍ଧି ରେ ସଠିକ୍ ନ ଥିଲେ ! ଆମର ବିଶ୍ବ ର ଭୌତିକ ସଂରଚନା ରେ ଅନେକ ଅଖାପ କିଂବା ଅଣ-ସଂବନ୍ଧି ଅମେଳ ଦୃଶ ହେଲେ ଯାହା ଭୌତିକ ପ୍ରବୃତ୍ତୀ ର ରହସ୍ୟପୁର୍ଣ୍ଣ ଚରିତ୍ରବତ୍ତା କୁ ସୁଚାଉ ଥିଲେ, ଯଥା ଘନ-ଶରୀର ପ୍ରଭା-ବ୍ୟାପକତା (black-body spectrum) ! ଏହି ପ୍ରଭା-ବ୍ୟାପକତା ରେ ନିମ୍ନ ଶକ୍ତୀ ସ୍ତର ର ଅବସ୍ଥାନ କରିବା ସୁଚାଏ ଯେ ସେଥିରେ କଣିକାଖଣ୍ଡ ପ୍ରବୃତ୍ତୀ ଥାଏ ଏବଂ ଉଚ୍ଚ ଶକ୍ତୀ ସ୍ତର ର ଅବସ୍ଥାନ କରିବାସୁଚାଏ ଯେ ସେଥିରେ ତରଂଗ ବା ଅନେକର୍ଣ୍ଣ-କଣିକାଖଣ୍ଡ ପ୍ରବୃତ୍ତୀ ଥାଏ ! ସମ୍ପୁର୍ଣ୍ଣ-ସତ୍ତା ଅର୍ଥ ରେ ଏ ସବୁ ରେ ତରଂଗ-କଣିକାଖଣ୍ଡ ପ୍ରବୃତ୍ତୀ ଅବସ୍ଥାନ କରେ ! ଏ ସମସ୍ତ ଜ୍ଞାନ “ସଠିକତା ର ଅଭାବ” ମଧ୍ୟ ରେ ଲୁଚି ରହି ଥିଲା ଠିକ୍ ଏପରି ଏକ ମହାନତା ଯେମିତିକି “ତୁମର ଯୋତା” ! ଯୋତା-ପ୍ରବନ୍ଧକ ର ବିଦ୍ଧି-ନିଦେଶ କୁ ପବିତ୍ର-ସଂକେତ ମନେ କରିବା କୁ ମନା କରିଦେବା ଦ୍ବାରା ବସ୍ତୁ-ବିଦ୍ ମାନେ ଅନାଦୃତ ବିଧୌତ-ମୁଣି ହେଇ ଗଲେ ନାଃହିଂ ବରଂଚ ଏହା ଦ୍ବାରା ସେମାନେ ନବକଳ୍ପିତ ଜ୍ଞାନ ର ସମ୍ଭାଷଣ କୁ ଆଦୃତ କରାଇଲେ ! ତଥା ତୁମେ ସୁରକ୍ଷିତ ମଣି କହି ପାରିବ ଯେ ସମସ୍ତ ଖଣ୍ଡଚଳ ନିୟମ ଏବଂ ସାଧାରଣ-ଆପେକ୍ଷିକତା ତଥା ନିର୍ଦିଷ୍ଟ ଆପେକ୍ଷିକତା ର ଦୁନିଆ ଯୋତା ର ଧାର ମଧ୍ୟ ରେ ଲୁଚ୍ଚାୟିତ ଥିଲା.
The frequency of light is small because the energy or intensity is low. So you see twinkles. But light is still moving at the same speed towards us. It takes 4.5 years from some stars while taking 8 minutes from sun, both at the same speed. But with sun, the face of the sun or angles on face of sun are rotating really fast. That rotation gives us the energy and momentum but the speed at which they all move is still c.
The fact that zero mass particles exist simply might be a coincidence of nature, that a very small energy was produced randomly. Again since it transmitted a longer distance or infinite distance might only happen for EM force only because of the nature of phenomena. Probably we need to think more why, what are any fundamental differences between different fundamental forces.
Xc; Every scientist has a high degree of respect towards Tesla including me. We use many of his inventions. Having said that in Nikola Tesla’s days particle acceleration technology was almost nonexistent. The current energy we reach is only a current technology. Naturally occurring high energy particles constantly hit earth atmosphere such as extremely high energy cosmic rays but it does not do us much harm. But if he actually gave such an interview (there are other websites also mentioning this interview) he was hallucinating as he did not understand the nitty gritties but it is impossible to send electric currents (thats what beams are) in open air that too for 250 miles. People believed him for his reputation but remember Einstein has come out plain wrong on many physics problems and his compatriots understood this far better than we do at present. Just one thing comes to my mind what Feynman said: No one is a pope in science … compare that to lightning, how it spreads everywhere, he could not have produced lightning for that sake, he should have thought a little more.
Think of force as the tension in a string. See force is present when you stretch a string or a thread. Thats elementry knowledge. So if to stretch the same thread or string I give you 4 different forces then you will need more gravity force to stretch the same amount, you will need less weak-nuclear force than the gravity force to stretch the same amount. You will need more weak-nuclear force to stretch the thread than the electromagnetic force for the same stretching. You need more electromagnetic force to stretch the same amount of the thread than you need strong-nuclear force. In other words the Young’s modulus of strong force is less than that of electromagnetic, Young’s modulus of electromagnetic force is less than that of weak and that of weak is less than that of gravity. Which means length of thread being same the stress produced by strong force is less than that of electromagnetic, is less than that of weak, is less than that of gravity. In other words “Hawking like wit”; A man who is stressed more has more gravity force acting on him. My wife is usually stressed out more because she is sensitive to the galaxy scale, she thinks about the galaxy even when she had to think about only her neighbourhood .. 笑 笑 笑笑 笑.
A clock is a device that knows how much energy is input and at what “time” rate. Time-rate can be arbitrary in nature but NOT in a clock. A clock is an anthropic time device. A clock is designed to know what energy is spent for a predefined uniform rate of spending that energy so that, that uniform rate is called time. But time in nature can be understood by studying any energy devices. To understand their uniformity [flatness] and design is called Physics. Every physical device is a clock. We just may not know howto read them.
Then each of these no-place-no-time-no-matter-no-energy bubbles can have a small amount of matter-energy-place-time, Heisenberg license is revoked and conservation principles are sacrosanct again. So that small license is the key to understanding how a small desirable violation of the laws of nature known in our scales today we do not throw scientific thinking into a pool of unsavory gel.