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July 30, 2017

Halliday resnick krane 5th edition

Halliday resnick krane 5th edition 

This book includes both part 1 and part 2 of the book. 




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July 19, 2017

Fsc physics notes of point part 1 and part 2

Important points of Physics Part 1 and part 2

Part 1

1.Value of "g" remains constant in the range of 1km.
2.Area under v-t graph gave distance.
3. Fnet=0 , ∆a=0 , ∆v does not equal to zero. The body will move with constant velocity.
4. When a triangle have two sides equal then there angle will also be equal.
5.increase in K.E=4 times
Momentum=?
P=√2mE
P= 2 times
6. Every declaration is not retardation acceleration but every retardation acceleration is deceleration.
7. Rocket propulsion involved Newton's 3rd law of Motion.
8. In Equation of motion , the acceleration is uniform.
9. One second is defined as 9192631770 periods of Cesium clock.
10. The magnitude of dot product and cross product will be same at 45° and 225°.
11. In stationary wave pressure is maximum at node and minimum at anti-node.
12. For Resonance;
i- Amplitude large
ii- Frequencies match
iii- Response must
13. Speed of sound in ;
i- solid 5000m/S
ii- liquid 1500m/s
iii- Gas 332m/s and vaccum zero.
14.Sound waves cannot be polarized because they are Longitudinal Waves.
15. Human ear can listen
20Hz-20000Hz
Infrasonic< 20Hz and 20000Hz<Ultrasonic
16. Same medium. Different medium
V=f x lambda. V= f x lambda
V remains constant. f remains constant.
Diffraction. Refraction
17. Speed of sound depends upon;
i- pressure
ii- increase in temp
iii- molecular weight
18. The wave which start from extreme position called cosine wave.
19. Sine wave starts from mean position.
20. Pyrometer used to measure pressure and Barometer used for high and low pressure.
21. For a satellite orbiting around earth P.E is greater than K.E.
22. Dyrometer:- Energy measurements.
23. K.E is inversaly proportional to moment of inertia.
24. Acceleration describes path motion followed by body.
25.No. Of beats per second= Diff of frequencies (beats)
26. S.H.M is a type rectilinear motion.
27. Linear Magnification
M= infinite
28. Resolving power inversaly proportional to wavelength and directly proportional to Diameter.
29. In YDSE wavefront divided.
30. Distance b/w object and its real image formed by convex lens cannot be less than 4f.
31. At the point if contact of lens and glass plate thickness is zero.
That's why Newton's centre is dark.
32. When object is placed B/w principle axis and focus image is erect, virtual and enlarge.
33. Focal length of directly proportional to wavelength means maxi for red and mini for violet.
34. The reason of seeing sun earlier of sunrise is refraction of light.
35. Rainbow form due to dispersion and total internal reflection combination.
36. When water heat
0° - 4° volume decrease
5°- 100° volume increases.
37. CNG engine efficiency= 18%
Petrol engine=25%
Disel engine =40-45%
38.change in entropy in adiabatic is zero.
39. We cannot see through the fog due to scattering.
40. Scattering inversaly proportional to wavelength.
41. Response for yellow-green light human eye is 5500A°.
42. Intensity becomes half after polarization.
43. Stars seems twinkle due to different refractive index in atmosphere of earth.
44. Newton's rings formed due to interference.
45.total internal reflection conditions;
i- Denser to rare.
ii- incidence angle > critical angle.
46.Entropy of gases is greater than the solids.
47. Real gases can obey gas law for
High temp and low pressure.

Part 2

1. When electrons removed from neutral metal electric charge on it is +1.6C.
2. Metal cannot be used as electric medium B/w plates of capacitor.
3. A charged conductor has charge on its outer surface.
4. Glass has losely bounded electrons.
5. Glass used B/w parallel plate capacitor to increase capacitance.
6. Work done in carrying a unit charge b/w two points on an equipotential is zero.
7. Flux density is a vector quantity.
8. Tensor is a quantity which have different values in different directions.
9. Mass of Alpha particle is 4 times of mass of proton.
10. Charge on alpha particle is 2 times of proton.
11. A device is non ohmic its resistance is dynamic.
12. A hollow charged surface does not produce E at internal.
13.when supply us given to a transfer its output voltage is zero volt.
14. The electrical circut used to got smooth D.C output for a rectifier is called Filter.
15. A hot body will rediate maxi energy if its surface is Black and rough.
16. Diode can't perform amplification because it is a two terminal device.
17. A choke coil have high inductance and low resistance. It control current due to Lenz's law.
18. The value of A.C produces heat is called virtual value.(Ch # 16 article before three phase)
19. In Hysteresis magnetizing current leads the magnetism.
20. Potential drop not depend upon temp.
21. A fast reactor does not use a moderator. i.e Uranium does not need a moderator.
22. Lyman series lies in both absorption and emissions.
23. Compound micro scope theory explained by liquid drop theory.
24. Fusion reaction is a source of energy in Hydrogen bomb and sun.
25. Fission reaction produces energy 0.9MeV per nucleon.
26. Fussion reaction produces energy 6MeV per nucleon.
27. A photon is always consideres to moving with speed of light.
28. Leptrons are electron , neutrino and anti-neutrino.
29. Proton and neutron are called nucleon.
30. The meaning of negative energy in a system indicate Bound energy.
31. Gamma particles are more penetrating but alpha are most dangerous for body.
32. Entering Flux is +ve and outgoing flux is -ve.
33. Ohm's law is only applicable to conductors.
34. Drift velocity cannot be increased by temp.
35. Magnetic field toward reader shows by X(outward).
36. Because of ionization of salt conductivity increases( last year this was appered in ECAT).
37. Current obtained by generator is displacement current.
38. The conductivity of super conductor is infinite.
39. Energy stored in chowk coil in the form of magneitc energy.
40. The best matriel for core of transformer is soft iron.
41. The energy produced in fussion reaction is 6 times more than a fission reaction.
42. Fussion takes place on earth only in Hydrogen bomb.
43. An op-amp consists of total 5 terminals.
44. Neutrons are more damaging for eyes.
45. Laser is used in micro surgery.
46.Fission reaction was discovered by two German scientists who Ottottann and Strassman in
1939.
47. Einstien photoelectric effect base upon conservation of mass.
48. Nuclear forces are short range and charge independent.
49. Penetrating power of X rays can be increased by frequency.
50. D.C have zero Frequency.
51. Good matriel for making Electro magnet is Iron.
52. Admittance is reciprocal of impedance.

November 11, 2015

Space-Time Review

                                           

                Space-Time Review

Space time is like a manifold woven of space and time,When any terretial body moves through it both space and time are changed.Einstein said time is what we measure with clock.I would not get to caught up in time it has an illusiory nature.                                                      Time is the medium in which everything happened. Space is the area or volume that matter and its waves occupy. Time quantifies change. Since all matter in the universe vibrates, it's state and position are always changing. Time is the measure of those changes. Without matter both space and time would be meaningless and would not exist.

                                  



According to Einstein Gravity is not a force but a curvature in space-time.





August 01, 2015

Einstein Mass energy equillance


April 11, 2015

Angualr momentum in term of spherical polar coordinates






                                                         
To download in Pdf File below



April 10, 2015

BLACK HOLE

         BLACK HOLE
Black holes are some of the strangest and most fascinating objects found in outer space. They are objects of extreme density, with such strong gravitational attraction that even light cannot escape from their grasp if it comes near enough. Albert Einstein first predicted black holes in 1916 with his general theory of relativity.                                                                  
The Black Hole, in the 1970s. It was about a space ship that was sent to investigate a black hole that had been discovered. It wasn't a very good film, but it had an interesting ending. After orbiting the black hole, one of the scientists decides, the only way to find out what is going on, is to go inside .So he gets into a space probe, and dives into the black hole. After a screen writer's depiction of Hell, he emerges into a new universe. This is an early example of the science fiction use of a black hole as a wormhole, a passage from one universe to another, or back to another location in the same universe. Such wormholes, if they existed, would provide short cuts for Interstellar  space travel, which otherwise would be pretty slow and tedious, if one had to keep to the Einstein speed limit, and stay below the speed of light.
In fact, science fiction writers should not have been taken so much by surprise. The idea behind black holes, has been around in the scientific community for more than 200 years. In 1783, A Cambridge don, John Michell, wrote a paper in the Philosophical Transactions of the Royal Society of London, about what he called dark stars. He pointed out that a star that was sufficiently massive and compact, would have such a strong gravitational field that light could not escape. Any light emitted from the surface of the star, would be dragged back by the star's gravitational attraction, before it could get very far. Michell suggested that there might be a large number of stars like this. Although we would not be able to see them, because the light from them would not reach us, we would still feel their gravitational attraction. Such objects are what we now call black holes, because that is what they are, black voids in space. A similar suggestion was made a few years later, by the French scientist the Marquis de La~plass, apparently independently of Michell.
Both Michell and La~plass thought of light as consisting of particles, rather like cannon balls, that could be slowed down by gravity, and made to fall back on the star. But a famous experiment, carried out by two Americans, Michelson and Morley in 1887, showed that light always traveled at a speed of one hundred and eighty six thousand miles a second, no matter where it came from. How then could gravity slow down light, and make it fall back. This was impossible, according to the then accepted ideas of space and time. But in 1915, Einstein put forward his revolutionary General Theory of Relativity. In this, space and time were no longer separate and independent entities. Instead, they were just different directions in a single object called space-time. This space-time was not flat, but was warped and curved by the matter and energy in it. In order to understand this, considered a sheet of rubber, with a weight placed on it, to represent a star. The weight will form a depression in the rubber, and will cause the sheet near the star to be curved, rather than flat. If one now rolls marbles on the rubber sheet, their 
paths will be curved, rather than being straight lines. In 1919, a British expedition to West Africa, looked at light from distant stars that passed near the Sun during an eclipse. They found that the images of the stars, were shifted slightly from their normal positions. This indicated that the paths of the light from the stars, had been bent by the curved space-time near the Sun. General Relativity was confirmed.
Consider now placing heavier and heavier, and more and more concentrated weights on the rubber sheet. They will depress the sheet more and more. Eventually, at a critical weight and size, they will make a bottomless hole in the sheet, that particles can fall into, but nothing can get out of. 

What happens in space-time according to General Relativity, is rather similar.  A star will curve and distort the space-time near it, more and more, the more massive and more compact the star is. If a massive star that has burnt up its nuclear fuel, cools and shrinks below a critical size, it will quite literally make a bottomless hole in space-time, that light can't get out of. Such objects were given the name, black holes, by the American physicist, John Wheeler, who was one of the first to recognize their importance, and the problems they pose. The name caught on quickly. It suggested something dark and mysterious, But the French, being French, saw a more risky meaning. For years, they resisted the name, troo noir, claiming it was obscene. But that was a bit like trying to stand against ~le week end, and other franglay. In the end, they had to give in.Who can resist a name that is such a winner.

From the outside, you can't tell what is inside a black hole. You can throw television sets, diamond rings, or even your worst enemies into a black hole, and all the black hole will remember, is the total mass, and the state of rotation. John Wheeler called this, A Black Hole Has No Hair. To
 The French, this just confirmed their suspicions.

A black hole has a boundary, called the event horizon. It is where gravity is just strong enough to drag light back, and prevent it escaping. Because nothing can travel faster than light, everything else will get dragged back also. Falling through the event horizon, is a bit like going over Niagra Falls in a canoe. If you are above the falls, you can get away if you paddle fast enough, but once you are over the edge, you are lost. There’s no way back. As you get nearer the falls, the current gets faster. This means it pulls harder on the front of the canoe, than the back. There’s a danger that the canoe will be pulled apart. It is the same with black holes. If you fall towards a black hole feet first, gravity will pull harder on your feet than your head, because they are nearer the black hole. The result is, you will be stretched out longwise, and squashed in sideways. If the black hole has a mass of a few times our sun, you would be torn apart, and made into spaghetti, before you reached the horizon. However, if you fell into a much larger black hole, with a mass of a million times the sun, you would reach the horizon without difficulty. So, if you want to explore the inside of a black hole, choose a big one. There is a black hole of about a million solar masses, at the center of our Milky Way galaxy. 
Although you wouldn't notice anything particular as you fell into a black hole, someone watching
You from a distance, would never see you cross the event horizon. Instead, you would appear to slow down, and hover just outside. You would get dimmer and dimmer, and redder and redder, until you were effectively lost from sight. As far as the outside world is concerned, you would be lost forever. Because black holes have no hair, in Wheeler's phrase, one can't tell from the outside what is inside a black hole, apart from its mass and rotation. This means that a black hole contains a lot of information that is hidden from the outside world. But there's a limit to the amount of information, one can pack into a region of space. Information requires energy, and energy has mass, by Einstein's famous equation,
     E = mc2 So if there's too much information in a region of space, it will collapse into a black hole, and the size of the black hole will reflect the amount of information. It is like piling more and more books into a library. Eventually the shelves will give way, and the library will collapse into a black hole. 
If the amount of hidden information inside a black hole, depends on the size of the hole, one would expect from general principles, that the black hole would have a temperature, and would glow like a piece of hot metal. But that was impossible, because as everyone knew, nothing could get out of a black hole. Or so it was thought, but I discovered that particles can leak out of a black hole. The reason is, that on a very small scale, things are a bit fuzzy. This is summed up in the uncertainty relation, discovered by Werner Heisenberg in 1923, which says that the more precisely you know the position of a particle, the less precisely you can know its speed, and vice versa. This means that if a particle is in a small black hole, you know its position fairly accurately. Its speed therefore will be rather uncertain, and can be more than the speed of light, which would allow the particle to escape from the black hole. The larger the black hole, the less accurately the position of a particle in it is defined, so the more precisely the speed is defined, and the less chance there is that it will be more than the speed of light. A black hole of the mass of the sun, would leak particles at such a slow rate, it would be impossible to detect. However, there could be much smaller mini black holes. These might have formed in the very early universe, if it had been chaotic and irregular. A black hole of the mass of a mountain, would give off x-rays and gamma rays, at a rate of about ten million Megawatts, enough to power the world's electricity supply. It wouldn't be easy however, to harnass a mini black hole. You couldn't keep it in a power station, because it would drop through the floor, and end up at the center of the Earth. About the only way, would be to have the black hole in orbit around the Earth. 

People have searched for mini black holes of this mass, but have so far, not found any. This is a pity, because if they had, I would have got a Nobel Prize. Another possibility however, is that we might be able to create micro black holes in the extra dimensions of space time. According to some theories, the universe we experience, is just a four dimensional surface, in a ten or eleven dimensional space. We wouldn't see these extra dimensions, because light wouldn't propagate through them, but only through the four dimensions of our universe. Gravity, however, would affect the extra dimensions, and would be much stronger than in our universe. This would make it much easier to form a little black hole in the extra dimensions. It might be possible to observe this at the LHC, the Large Hadron Collider, at Cern, in Switzerland. This consists of a circular tunnel, 27 kilometers long.Two beams of particles travel round this tunnel in opposite directions, and are made to collide. Some of the collisions might create micro black holes. These would radiate particles in a pattern that would be easy to recognize. So, I might get a Nobel Prize, after all. 
As particles escape from a black hole the hole will lose mass, and shrink. This will increase the rate of emission of particles. Eventually, the black hole will lose all its mass, and disappear. What then happens to all the particles and unlucky astronauts that fell into the black hole? They can't just re-emerge when the black hole disappears. The particles that come out of a black hole, seem to be completely random, and to bear no relation to what fell in. It appears that the information about what fell in, is lost, apart from the total amount of mass, and the amount of rotation. But if information is lost, this raises a serious problem that strikes at the heart of our understanding of science. For more than 200 years, we have believed in scientific determinism, that is, that the laws of science, determine the evolution of the universe. This was formulated by La~plass as, If we know the state of the universe at one time, the laws of science will determine it at all future and past times. Napoleon is said to have asked La~plass how God fitted into this picture. La~plass replied, Sire, I have not needed that hypothesis. I don't think that La~plass was claiming that God didn't exist. It is just that He doesn't intervene, to break the laws of Science. That must be the position of every scientist. A scientific law, is not a scientific law, if it only holds when some supernatural being, decides to let things run, and not intervene.  

In La~plass's determinism, one needed to know the positions and speeds of all particles at one time in order to predict the future. But according to the uncertainty relation, the more accurately you know the positions, the less accurately you can know the speeds, and vice versa. In other words, you can't know ~both the positions, ~and the speeds, accurately. How then can you predict the future accurately? The answer is, that although one can't predict the positions and speeds separately, one ~can predict what is called, the quantum state. This is something from which both positions and speeds can be calculated, to a certain degree of accuracy. We would still expect the universe to be deterministic, in the sense that if we knew the quantum state of the universe at one time, the laws of science should enable us predict it at any other time. 

If information were lost in black holes, we wouldn't be able to predict the future, because a black hole could emit any collection of particles. It could emit a working television set, or a leather bound volume of the complete works of Shakespeare, though the chance of such exotic emissions is very low. It is much more likely to be thermal Radiation, like the glow from red hot metal.  It might seem that it wouldn't matter very much if we couldn't predict what comes out of black holes. There aren't any black holes near us. But it is a matter of principle. If determinism breaks down with black holes, it could break down in other situations. There could be virtual black holes that appear as fluctuations out of the vacuum, absorb one set of particles, emit another, and disappear into the vacuum again. Even worse, if determinism breaks down, we can't be sure of our past history either. The history books and our memories could just be illusions. It is the past that tells us who we are. Without it, we lose our identity. 

It was therefore very important to determine whether information really was lost in black holes, or whether in principle, it could be recovered. Many people felt that information should not be lost, but no one could suggest a mechanism by which it could be preserved. The arguments went on for years. Finally, I found what I think is the answer. It depends on the idea of Richard Fein man, that there isn't a single history, but many different possible histories, each with their own probability. In this case, there are two kinds of history. In one, there is a black hole, into which particles can fall, but in the other kind, there is no black hole. The point is, that from the outside, one can't be certain whether there is a black hole, or not. So there is always a chance that there isn't a black hole. This possibility is enough to preserve the information, but the information is not returned in a very useful form. It is like burning an encyclopedia.. Information is not lost if you keep all the smoke and ashes, but it is difficult to read. Kip Thorne and I had a bet with John Preskill, that information would be lost in black holes. When I discovered how information could be preserved, I conceded the bet. I gave John Preskill an encyclopedia. Maybe I should have just given him the ashes. 
What does this tell us about whether it is possible to fall in a black hole, and come out in another universe? The existence of alternative histories with black holes, suggests this might be possible. The hole would need to be large, and if it was rotating, it might have a passage to another universe. But you couldn't come back to our universe. So, although I'm keen on space flight, I'm not going to try that. 

The message of this lecture, is, that black holes ain't as black as they are painted. They are not the eternal prisons they were once thought. Things ~can get out of a black hole, both to the outside, and possibly, to another universe. So, if you feel you are in a black hole, don't give up. There's a way out.

 Most famously, black holes were predicted by Einstein's theory of general relativity, which showed that when a massive star dies, it leaves behind a small, dense remnant core. If the core's mass is more than about three times the mass of the Sun, the equations showed, the force of gravity overwhelms all other forces and produces a black hole.
Nearest black hole to Earth is astoundingly close, just 1,600 light-years away. Not close enough to be considered dangerous, but way closer than thought. Further research, however, shows that the black hole is likely further away than that. Looking at the rotation of its companion star, among other factors, yielded a 2014 result of more than 20,000 light years.

Cygnus X-1 was first found during balloon flights in the 1960s, but wasn’t identified as a black hole for about another decade. According to NASA, the black hole is 10 times more massive to the Sun. Nearby is a blue supergiant star that is about 20 times more massive than the Sun, which is bleeding due to the black hole and creating X-ray emissions.
There are at least three types of black holes, NASA says, ranging from relative squeakers to those that dominate a galaxy’s center. Primordial black holes are the smallest kinds, and range in size from one atom’s size to a mountain’s mass. Stellar black holes, the most common type, are up to 20 times more massive than our own Sun and are likely sprinkled in the dozens within the Milky Way. And then there are the gargantuan ones in the centers of galaxies, called “supermassive black holes.” They’re each more than one million times more massive than the Sun. How these beasts formed is still being examined.
The term "black hole" was coined in 1967 by American astronomer John Wheeler, and the first one was discovered in 1971.Black holes have three "layers" — the outer and inner event horizon and the singularity. The event horizon of a black hole is the boundary around the mouth of the black hole where light loses its ability to escape. Once a particle crosses the event horizon, it cannot leave. Gravity is constant across the event horizon. The inner region of a black hole, where its mass lies, is known as its singularity, the single point in space-time where the mass of the black hole is concentrated. Under the classical mechanics of physics, nothing can escape from a black hole. However, things shift slightly when quantum mechanics are added to the equation. Under quantum mechanics, for every particle, there is an antiparticle, a particle with the same mass and opposite electric charge. When they meet, particle-antiparticle pairs can annihilate one another. If a particle-antiparticle pair is created just beyond the reach of the event horizon of a black hole, it is possible to have one drawn into the black hole itself while the other is ejected. The result is that the event horizon of the black hole has been reduced and black holes can decay, a process that is rejected under classical mechanics. Scientists are still working to understand the equations by which black holes function. In many ways a black hole acts like an ideal black body.
General Theory of Relativity:
It is based on two principles
1) if you have two objects nothing else,then it is not possible to tell which object is moving and which object is standing still.this is even true if one object is an entire planet.
A man in space ship,the spaceship is standing still and it is the planet that is moving.
After all from the prospective of third obsever.in general any observer can believe that they are standing still and the rest of universe is moving around and every observer is equally correct.
2 )Speed of light is samefor all absservers
Spaceship approaches the speed of light the slower the time will flow inside the space ship.if the speed of spaceship approaches to the speed of light then time inside the spaceship would stop together.As an object moves with more energy its mass increases,this why nothing can travel with speed of light.gravity is not a force but a curvature in space-time.
Whermhole is a theoracticall tunnel providing shortcuts through space and time to travel between different parts of universe.
In 1930 neithe rozen and Einstein mathematical caluculations for black hole.
In late 199’s carl sagan  purpose that whormhole can be used for space travell apple example
LISA:Laser Inferometer Space antenna join nasa and Europe space egency mission.
Switzerland sarn experiment done on black hole creation.

In 1971,atomic clock slight difference.

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March 10, 2015

Zero point Energy in Quantum Mechanics

              Zero point Energy in Quantum Mechanics

                           Zero Point energy:-
                            It is also called quantum vacuum zero-point energy and is the lowest possible energy that a quantum mechanical Physical System may have. It is the energy of its ground state. All quantum mechanical systems undergo fluctuations even in their ground state and have an associated zero-point energy, a consequence of their wave like nature. The uncertainty principle requires every physical system to have a zero-point energy greater than the minimum of its classical potential well. Also Zero point energy is the energy that remains when all other energy is removed from the system. This behavior is demonstrated by, for example, liquid helium. As the temperature is lowered to absolute zero, helium remains a liquid, rather than freezing to a solid, owing to the irremovable zero-point energy of its atomic motions. (Increasing the pressure to 25 atmospheres will cause helium to freeze.) Where ''zero-point'' refers to the energy of the system at temperature T=0, or the lowest quantized energy level of a quantum mechanical system.
     Harmonic Oscillator
Classically a harmonic oscillator, such as a mass on a spring, can always be brought to rest. However a quantum harmonic oscillator does not permit this. A residual motion will always remain due to the requirements of the Heisenberg uncertainty principle, resulting in a zero-point energy, equal to 1/2 hf, where f is the oscillation frequency.
                          

 This energy value is for three reasons First, the energies are quantized, meaning that only discrete energy values (integer-plus-half multiples of ħω) are possible; this is a general feature of quantum-mechanical systems when a particle is confined. Second, these discrete energy levels are equally spaced, unlike in the bhor model of the atom, or the particle in a box. Third, the lowest achievable energy (the energy of the n = 0 state, called the ground state) is not equal to the minimum of the classical potential well, but ħω/2 above it; this is called Zero-point energy. Because of the zero-point energy, the position and momentum of the oscillator in the ground state are not fixed (as they would be in a classical oscillator), but have a small range of variance, in accordance with the Heisenberg’s uncertainty principle. This zero-point energy further has important implications in quantum field theory and quantum gravity.

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February 23, 2015

Quantum Mechanics By Nouredine Zettili

Quantum Mechanics concepts and Application By Nouredine Zettili 2nd Edition.

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January 21, 2015

Photo-electric effect

                   Photo-electric effect

Definition:-
                      When light of suitable frequency falls on metal surface, the electrons are emitted. These are called photo-electrons and process is known as “Photo electric effect”.
Experimental observation:-
     1)   The number of photo-electrons (photo-current) is directly proportional to the intensity of incident radiation.
     2)   It is spontaneous emission. Emission of electrons occurs immediately after the radiation falls on the surface.
    3)   Electrons are emitted from the metal surface, no matter the incident radiation is weaker in intensity. Emission of electrons from metal surface is independent of intensity of the radiation.
    4)   Emission of electrons depends upon the threshold frequency, if frequency of incident radiation is higher than the threshold frequency then electrons will be emitted without decay.
  Ø Above results cannot explained by the photo-electric effect. The classical theory cannot explain the threshold frequency of light.
  Ø The results cannot be explained on the basis of electromagnetic wave theory of light.

     Quantum mechanical Explanation:-

Einstein put forward Quantum mechanical explanation of the photo-electric effect using Planck’s black body radiation theory.

Theory:-
     1)    Incident radiation in photo-electric effect consist of tiny particles carry quanta of energy  called photon like tiny oscillator defined in black body radiation.                          E=hѵ
     2)    On interaction of those photons with electrons of metal. All of the energy of photons is transferred to electrons.
     3)    The acquired energy from photons by electrons is used up as follows.  
              Overcome the work-function of metal:-
     1)    Releases the electron from metal surface.
     2)    Remaining energy is converted into the K.E of the electrons.
Mathematically
i.e.                         hѵ= hѵ0 +K.E
0 =Work function     ѵ0 = Threshold frequency

                 Measurement of work function:-

K.E of emitted electrons i-e Photo electrons can be measured by collecting electrons at anode i-e at negative potential. The voltage at which Electrons are stopped is called as stopping potential.
Mathematically.
K.E=eѵ0             Where  ѵ0 = stopping potential
  Ø hѵ = hѵ0 +ev
h(ѵ- ѵ0) = K.E
If ѵ <ѵ0        Then     K.E< 0

Which is not true. Hence no electrons can be emitted from the metal surface if incidents frequency is less than threshold frequency. 

January 18, 2015

atomic and nuclear physics notes

                Atomic and molecular physics pdf notes

To learn physics of atom and molecules notes are given for the students of master level students of physics .Atomic physics lecture notes involves basic introduction, Fermi’s Golden Rule Quantum numbers, Bohr Theory, sommerfeld theory atomic model periodic table and much more.

To download atomic and molecular physics pdf notes click on the downloading button given below.
                 

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