HOW MODERN PHYSICS CHANGED THE WORLD???? FIND THE ANSWER BY MICHIO KAKU.
- The greatness of two scientists.once Satyendra Nath Bose sent his research paper to einstien,then new theory arised,as folllows.
- A (BEC) is a state of matter of a dilute gas of bosons cooled to temperatures very close to absolute zero . Under such conditions, a large fraction of the bosons occupy the lowest quantum state, at which point quantum effects become apparent on a macroscopic scale. These effects are called
“macroscopic quantum phenomena”.
- Bose first sent a paper to Einstein on the quantum statistics of light quanta (now called photons). Einstein was impressed, translated the paper himself from English to German and submitted it for Bose to the Zeitschrift für Physik, which published it. (The Einstein manuscript, once believed to be lost, was found in a library at Leiden University in 2005.Although later experiments have revealed complex interactions, this state of matter was first predicted, generally, in papers by Satyendra Nath Bose and Albert Einstein in 1924–25.
- BEC occurs below a critical temperature, which for a uniform three-dimensional gas consisting of non-interacting particles with no apparent internal degrees of freedom is given by:
friends do you know the special properties of light…in ancient
days the speed and its propertis are observed on the basis of physical existence…and more clearly i can say by observing nature of light that what we see from our eyes.
newton is one of them who started to observe the light from eyes differently..what a joke all we see from our eyes only..then what different newton had seen? confused let me explain arund 1690 newton started his studies on light.he used the special instrument called prism.now a days prism is common.but in 16th century,newton used it as one of great science device,to reveal the secrets of light. he saw not only light,but the colour full light emeging from prism.(VIBGYOR)this is what i said.in history mankind newton is the first person to observe,such phenonmenon.for today its a simple thing. and started to give his conclsions.he briefly started to study optics.and writen his book ‘Optics’.
but let me give some properties which cannot be explaind by just looking through naked eyes.
1)Light can move through vacuum.
2)Light transports energy.
3)Light has angular momentum: it can rotate bodies.
4)Light has momentum: it can collide the particles.
5)a special property friends my future blog will be on this,light moves with other light undisturbedly..
6)Light in outerspace moves faster than all objects in this universe..
7)The speed of light, its true signal speed, is the forerunner speed. Vol. III, page 118
8)299 792 458m/s is the speed of light in vaccum.and 30c.m/n.s(30 centimeter per nano seconds.1/1000000000.
9)The proper speed of light is infinite.(credit:motion mountain_relativity)
10)Shadows can move without any speed limit.(credit:motion mountain_relativity)
11)Light moves in a straight line when far from matter.
12)High-intensity light is a wave.(credit:motion mountain_relativity)
13)Light beams are approximations when the wavelength is neglected.
14)In matter, both the forerunner speed and the energy speed of light are lower than in vacuum.
15)In matter, the group velocity of light pulses can be zero, positive, negative or infinite.these are the properties of light which are gifts of quantum physics.or modern physics..the era of quantum physics was began in 1905(see my previous post for more information)this changed the world into quantum world.and some property of light is very strange and it was an miracle thing for ancients,hence may be miracle must be reveled as common thing,so people from 1000s of years started to study and open the well of lightening light information gradually.i hope you understood.thanks for reading.
Weight and Mass
friends this is the same question i too got when i was small boy. now i’m going to explain it in this article…i hope you’ll read it.
The word weight was used above to denote the force with which the book pressed on the table as a consequence of the gravitational force of attraction between the Earth and the book, and Newton’s third law. Here we give a more rigorous definition of the term weight. Specifically,
friends since we know and we have learnt also forces are measured in Newtons, so is weight. An analogous definition for the weight of an object on the moon or any other planet can also be made. We thus see that the weight of an object is different on different planets, as the force of attraction would be different (this force depends on the planet’s mass and radius). Even on earth, weight changes with changing altitude: the higher up you go, the less force the earth exerts on you, and hence your weight decreases. Ultimately one reaches a height where the earth exerts negligible force on you, and you experience weightlessness. We will learn more about gravity, and how it varies from place to place and planet to planet,
From the above discussion we see that mass and weight cannot strictly speaking be equivalent. Mass is the resistance of an object to a change in its motion, while weight is the gravitational force of attraction between the object and the Earth. Mass and weight even have different units. Nonetheless, the terms weight and mass are sometimes used interchangeably. For example, when we weigh an object the result is sometimes given in kilograms, and sometimes in pounds. We learn while shopping that 454 grams of cherries is the same as 1 lb of cherries. However, in the British system of units the “pound” is a unit of force that is used as the standard unit of weight (the related unit of mass is called the “slug”, which is probably why the pound was adopted as the standard). The conversion to MKS units is given by
Newton’s second law plus a remarkable fact first discovered by Galileo can be used to provide us with a relationship between mass and weight that is implicitly used whenever something is said to “weigh” 1 kg, for example. Since force equals mass times acceleration, and weight is the force of gravity on an object we have that The remarkable fact realized by Galilean is that all objects accelerate towards the Earth at the same rate. You can verify this yourself by doing the following simple experiment. Hold a sheet of paper in one hand and your physics text book in the other, and drop them simultaneously from the same height above your desk. Do they hit the desk at the same time? The answer is no, but we know that the reason has to do with air resistance, which has more effect on the light piece of paper than on the heavy text book. Now if the piece of paper is just a bit smaller than the size of your textbook you can place the paper on top of the book, and drop the two together. You should find, quite dramatically, that the book and paper hit the desk at precisely the same instant. What is happening in this case is that the book is shielding the paper from the effects of air resistance, so that this experiment verifies the fact that:At sea level, this rate is 9.8 m/s2.
Going back to Newton’s 2nd law, the force on an object due to gravity, at sea level, must therefore be
The upshot of all this is that the weight of an object is proportional to its inertial mass and is completely independent of the object’s composition. Consequently, one kilogram of anything weighs 9.8 Newtons, and we can “convert” back and forth between kilograms and Newtons using the conversion factor of 9.8 Newtons per kilogram. This however should not be viewed as a simple conversion of units like between, for example, meters and kilometers; the weight and mass measure different things, whereas meters and kilometers are both units of distance. As a check, we recall that 1 pound is equivalent to 4.45 Newtons. “Converting” 4.45 Newtons to kilograms by dividing by 9.8 Newtons per kilogram we find that 1 pound is “equivalent” to
4.45 N/ (9.8 N/kg) = .454 kg .i hope you got it…thanks for reading…please check it out my recent posts.