What is Electric Charge ? Kinds and Coulomb's Law

WHAT IS ELECTRIC CHARGE ?

 Electric charge is the physical property of issue that makes it experience a power when put in an electromagnetic field. There are two sorts of electric charge: positive and negative (generally conveyed by protons and electrons individually). Like charges repulse one another and dissimilar to charges draw in one another. An article with a nonattendance of net charge is alluded to as unbiased. Early information on how charged substances cooperate is currently called old style electrodynamics, is as yet exact for issues that don't need thought of quantum impacts. 

1.Electric charges produce electric fields 2. A moving charge additionally creates an attractive field. 3. The cooperation of electric accuses of an electromagnetic field (mix of electric and attractive fields) is the wellspring of the electromagnetic (or Lorentz) force, 4. which is one of the four basic powers in material science. The investigation of photon-interceded associations among charged particles is called quantum electrodynamics 

The SI inferred unit of electric charge is the coulomb (C) named after French physicist Charles-Augustin de Coulomb. In electrical designing, it is likewise normal to utilize the ampere hour (Ah); in material science and science, it is entirely expected to utilize the rudimentary charge (e as a unit). Science additionally utilizes the Faraday steady as the charge on a mole of electrons. The lowercase image q frequently indicates charge.

Two Kinds Of Charge 

ll items encompassing us (counting individuals!) contain a lot of electric charge. There are two sorts of electric charge: positive charge and negative charge. In the event that similar measures of negative and positive charge are found in an item, there is no net charge and the article is electrically unbiased. In the event that there is a greater amount of one kind of charge than the other on the item then the article is supposed to be electrically charged. The image underneath shows what the dissemination of charges may resemble for an impartial, decidedly charged and contrarily charged item. 

Positive charge is conveyed by the protons in material and negative charge by electrons. The general charge of an item is typically because of changes in the quantity of electrons. To make an article: 

• positive charged: electrons are taken out making the item electron lacking. 

• negatively charged: electrons are included giving the item an overabundance of electrons.

Coulomb's Law

Coulomb's Law gives a thought regarding the power between two point charges. By the word point charge, we imply that in material science, the size of straight charged bodies is little as against the separation between them. Thusly, we consider them as point charges as it turns out to be simple for us to ascertain the power of fascination/shock between them. 

Charles-Augustin de Coulomb, a French physicist in 1784, estimated the power between two point energizes and he accompanied the hypothesis that the power is conversely corresponding to the square of the separation between the charges. He additionally found that this power is legitimately relative to the result of charges (extents as it were). 

We can show it with the accompanying clarification. Suppose that there are two charges q1 and q2. The separation between the charges is 'r', and the power of fascination/repugnance between them is 'F'. At that point 

F ∝ q1q2 

Or on the other hand, F ∝ 1/r2 

F = k q1q2/r2 

where k is proportionality consistent and equivalents to 1/4 π ε0. Here, ε0 is the epsilon nothing and it implies permittivity of a vacuum. The estimation of k comes 9 × 109 Nm2/C2 when we take the S.I unit of estimation of ε0 is 8.854 × 10-12 C2 N-1 m-2. 

As per this hypothesis, similar to charges repulse one another and dissimilar to charges draw in one another. This implies charges of same sign will push each other with loathsome powers while accuses of inverse signs will pull each other with alluring power.

Limitation of Coulomb's Law 

Coulomb's Law is determined under specific presumptions and can't be utilized unreservedly like other general recipes. The law is restricted to following focuses: 

• We can utilize the recipe if the charges are static ( in rest position) 

• The recipe is anything but difficult to utilize while managing charges of normal and smooth shape, and it turns out to be too mind boggling to even think about dealing with charges having sporadic shapes 

• The recipe is just legitimate when the dissolvable atoms between the molecule are adequately bigger than both the charges

What is magnet ? properties, Types, and magnetic field.

 What is magnet ?

Definition

A magnet is a material or item that delivers an attractive field. This attractive field is imperceptible yet is answerable for the most outstanding property of a magnet: a power that pulls on other ferromagnetic materials, for example, iron, and draws in or repulses different magnets.

properties

• At the point when a magnet is plunged in iron filings, we can see that the iron filings stick to the furthest limit of the magnet as the fascination is most extreme at the closures of the magnet. These finishes are known as shafts of the magnets. 
• Attractive shafts consistently exist two by two. 

• At whatever point a magnet is suspended uninhibitedly in mid-air, it generally focuses towards north-south heading. Pole pointing towards geographic north is known as the North Pole and the pole pointing towards geographic south is known as the South Pole. 

• Like shafts repulse while not at all like posts pull in. 

• The attractive power between the two magnets is more prominent when the separation between these magnets are lesser.

Types of magnets

there are three types of magnets .

• Permanent magnet
• Temporary magnet
• Electromagnets

permanent magnets

permanent magnets are those magnets that are regularly utilized. They are known as lasting magnets since they don't lose their attractive property once they are polarized. 

Following are the approaches to demagnetize the lasting magnets: 

Presenting magnets to outrageous temperatures. 

The attractive fascination between the magnet's iotas gets extricate when they are pounded. 

Stroking one magnet with the other in a wrong way will decrease the attractive quality. 

There are four kinds of perpetual magnets: 

Artistic or ferrite 

Alnico 

Samarium Cobalt (SmCo) 

Neodymium Iron Boron (NIB)

Temporary magnets

Transitory magnets can be polarized within the sight of an attractive field. At the point when the attractive field is taken out, these materials lose their attractive property. Iron nails and paper-cuts are instances of the brief magnet.

Electromagnets 

Electromagnets comprise of a curl of wire folded over the metal center produced using iron. At the point when this material is presented to an electric flow, the attractive field is produced causing the material to act like a magnet. The quality of the attractive field can be constrained by controlling the electric flow.

magnetic field

Attraction is one part of the joined electromagnetic power. It alludes to physical marvels emerging from the power brought about by magnets, protests that produce handle that draw in or repulse different articles. 

An attractive field applies a power on particles in the field because of the Lorentz power, as per Georgia State University's HyperPhysics site. The movement of electrically charged particles offers ascend to attraction. The power following up on an electrically charged molecule in an attractive field relies upon the size of the charge, the speed of the molecule, and the quality of the attractive field. 

All materials experience attraction, some more unequivocally than others. Perpetual magnets, produced using materials, for example, iron, experience the most grounded impacts, known as ferromagnetism. With uncommon special case, this is the main type of attraction sufficiently able to be felt by individuals.

Thomson's Model, Rutherford's model, Bohr's Model And It's Limitations.

 Thomson's Model, Rutherford's model, Bohr's Model And It's Limitations.

1. Thomson's model 

Thomson nuclear model was proposed by William Thomson in the year 1900. This model clarified the portrayal of an inward structure of the iota hypothetically. It was unequivocally upheld by Sir Joseph Thomson, who had found the electron before.

 

During cathode beam aube analyze, a contrarily charged molecule was found by J.J. Thomson. This examination occurred in the year 1897. Cathode beam tube is a vacuum tube. The negative molecule was called an electron.

 

Thomson accepted that an electron is multiple times lighter than a proton and accepted that an iota is comprised of thousands of electrons. In this nuclear structure model, he considered molecules encompassed by a cloud having positive just as negative charges. The show of the ionization of air by X-beam was additionally done by him along with Rutherford. They were the first to show it. Thomson's model of a molecule is like a plum pudding.

Limitations of Thomson's Model 

 

•  It neglected to clarify the dependability of a molecule since his model of iota neglected to clarify how a positive charge holds the contrarily charged electrons in a particle.

 

•  Hence, This hypothesis likewise neglected to represent the situation of the core in a particle

 

•  Thomson's model neglected to clarify the dispersing of alpha particles by slight metal foils

 

No trial proof in its help

2. Rutherford Model

The gold foil Experiments 

In 1911, Rutherford and colleagues Hans Geiger and Ernest Marsden started a progression of momentous analyses that would totally change the acknowledged model of the molecule. They besieged exceptionally flimsy sheets of gold foil with quick moving alpha particles. Alpha particles, a kind of normal radioactive molecule, are decidedly accused particles of a mass around multiple times that of a hydrogen iota.

 

As indicated by the acknowledged nuclear model, where an iota's mass and charge are consistently conveyed all through the molecule, the researchers expected that the entirety of the alpha particles would go through the gold foil with just a slight diversion or none by any means. Shockingly, while the majority of the alpha particles were to be sure undeflected, a tiny rate (around 1 of every 8000 particles) ricocheted off the gold foil at exceptionally enormous edges. Some were even diverted back toward the source. No earlier information had set them up for this revelation. In an adage, Rutherford shouted that it was "as though you had shot a 15-inch [artillery] shell at a bit of tissue paper and it returned and hit you."

 

Rutherford expected to concoct a totally new model of the iota so as to clarify his outcomes. Since by far most of the alpha particles had gone through the gold, he contemplated that a large portion of the iota was vacant space. Conversely, the particles that were exceptionally avoided probably encountered an immensely ground-breaking power inside the iota. He presumed that the entirety of the positive charge and most of the mass of the particle must be moved in an exceptionally little space in the molecule's inside, which he called the core. The core is the little, thick, focal center of the iota and is made out of protons and neutrons.

 

Rutherford's nuclear model got known as the atomic model. In the atomic particle, the protons and neutrons, which contain almost the entirety of the mass of the iota, are situated in the core at the focal point of the molecule. The electrons are dispersed around the core and involve the greater part of the volume of the molecule. It merits stressing exactly how little the core is contrasted with the remainder of the iota. On the off chance that we could explode a particle to be the size of an enormous expert football arena, the core would be about the size of a marble.

 

Rutherford's model end up being a significant advance towards a full comprehension of the particle. Be that as it may, it didn't totally address the idea of the electrons and the manner by which they consumed the tremendous space around the core. It was not until certain years after the fact that a full comprehension of the electron was accomplished. This end up being the way to understanding the concoction properties of components.

Limitations of Rutherford Model

•  Rutherford recommended that the electrons rotate around the core in fixed ways called circles. As indicated by Maxwell, quickened charged particles produce electromagnetic radiations and henceforth an electron rotating around the core ought to emanate electromagnetic radiation. This radiation would convey vitality from the movement of the electron which would come at the expense of contracting of circles. At last the electrons would fall in the core. Counts have indicated that according to the Rutherford model, an electron would fall in the core in under 10-8 seconds. So Rutherford model was not as per Maxwell's hypothesis and couldn't clarify the soundness of an iota. 

•  One of the disadvantages of the Rutherford model was likewise that he didn't utter a word about the game plan of electrons in an iota which made his hypothesis fragmented. 

•  In spite of the fact that the early nuclear models were wrong and neglected to clarify certain exploratory outcomes, they were the base for future improvements in the realm of quantum mechanics.
• 
  

Bohr's Model 

Bohr model of the particle was proposed by Neil Bohr in 1915. It appeared with the change of Rutherford's model of an iota. Rutherford's model presented the atomic model of a molecule, wherein he clarified that a core (emphatically charged) is encircled by adversely charged electrons.

 

Bohr changed this nuclear structure model by clarifying that electrons move in fixed orbital's (shells) and not anyplace in the middle of and he likewise clarified that each circle (shell) has a fixed vitality level. Rutherford essentially clarified the core of a particle and Bohr adjusted that model into electrons and their vitality levels. Bohr's model comprises of a little core (decidedly charged) encompassed by negative electrons moving around the core in circles. Bohr found that an electron found away from the core has more vitality, and electrons near the core have less vitality.

 Limitations of Bohr's Model 

•  Bohr's model of a molecule neglected to clarify the Zeeman Effect (impact of attractive field on the spectra of particles).

 

•  It additionally neglected to clarify the Stark (impact of electric field on the spectra of molecules).

 

•  It disregards the Heisenberg Uncertainty Principle.

 

What Is Electromagnetic Waves, types and Nature

What Is Electromagnetic Waves, types and Nature

About The Light Waves(electromagnetic waves)

You encircled by electromagnetic waves. They're all over the place! From the light you can see, to the infrared your body is creating, to the bright getting through your window from the sun. You were unable to get away from the waves in the event that you attempted. In any case, of course, for what reason would you need to? 

The term light waves can be utilized distinctively by various individuals. Physicists will in general calmly use 'light waves' to mean the very same thing as electromagnetic waves, however most non-physicists don't. Anyway, what is the distinction? 

Electromagnetic waves (or electromagnetic radiation) are waves made of swaying attractive and electric fields, and incorporate radio waves, microwaves, infrared, obvious light, bright, x-beams and gamma beams. Like all waves, they convey vitality, and that vitality can be exceptionally high-power (like the electromagnetic waves we get from the sun). When taking a gander at the noticeable light range, the blue finish of the electromagnetic range is high recurrence, high vitality and short frequency. The red finish of the electromagnetic range is low recurrence, low vitality and long frequency. 

Light is only one aspect of the electromagnetic range, the part that our eyes can see. So when a great many people talk about light waves, this is the thing that they mean. In any case, in material science, 'light waves' frequently allude to any waves in the electromagnetic range, and this is the thing that we will talk about in this exercise.

Many Types Of Light Waves.

1. Radio Waves

Radio waves are at the red finish of the electromagnetic range. The red end is additionally the most reduced vitality, the least recurrence and the longest frequency. 

Radio waves are generally utilized in interchanges, to impart signs starting with one spot then onto the next. Radio broadcasts, obviously, utilize radio waves, as do PDAs, TVs, and remote systems administration. Because of the long frequency of radio waves, they can be ricocheted off the Earth's ionosphere, permitting radio broadcasts to communicate their transmissions over significant distances, without being in view of every one of their audience members. 

2. Microwaves 

Microwaves are the following nearest to the red finish of the range. You can presumably figure that microwaves are utilized in our kitchen microwaves to prepare your food. They are of a sufficiently high vitality that they can expand the movement of the particles in your food without ionizing the iotas (permitting electrons to get away). This is significant, in light of the fact that it implies that the food might be warmed - its synthetic piece will continue as before. 

3.Infrared

Infrared has a frequency only somewhat longer than what our eyes can distinguish. The human body has a temperature that produces radiation in this aspect of the range, thus infrared locators can be utilized as night-vision cameras. Infrared is additionally utilized by controllers to impart signs to TVs and other AV gear. 

Noticeable light is the aspect of the electromagnetic range that our eyes can identify as is the part we are generally acquainted with in our regular daily existences. It is viewed as in the 'center' of the electromagnetic range, however this is genuinely self-assertive. 

UV Waves

 UV waves are sufficiently high vitality that they are equipped for ionizing particles, breaking atomic bonds and in any event, harming DNA atoms. Thus, it is UV that causes burn from the sun and, hence, skin disease. The majority of the sun's destructive UV waves are consumed by the air (particularly Nitrogen) and the ozone layer, yet enough overcomes that we must be cautious by wearing sunscreen and utilizing UV eye insurance. 

x- Rays

X-Rays are extremely high vitality and, similar to UV, they can ionize iotas in the body and cause harm. Notwithstanding, at the correct frequencies and in the correct amounts, they can be securely skiped off body tissues to make x-beam pictures of within the human body. X-beams are additionally made by neutron stars, dark gaps and nebulae, and x-beam telescopes are, consequently, valuable in astronomy research.

Nature Of Light Waves 

light is a cross over, electromagnetic wave that can be seen by the commonplace human. The wave idea of light was first outlined through examinations on diffraction and impedance. Like every single electromagnetic wave, light can go through a vacuum. The cross over nature of light can be shown through polarization. 

In 1678, Christiaan Huygens (1629–1695) distributed Traité de la Lumiere, where he contended for the wave idea of light. Huygens expressed that an extending circle of light carries on as though each point on the wave front were another wellspring of radiation of a similar recurrence and stage. 

Thomas Young (1773–1829) and Augustin-Jean Fresnel (1788–1827) refuted Newton's corpuscular hypothesis.

What is Material Science. definition, History, Mechanics.

 What Is material science??

Material Science is the Branch of ''Science''. And the study of Material.

The vast majority hear the word 'material science' and run for spread. However, it's not only for scientific geniuses! You are encircled by material science constantly, and whether you understand it or not, you use material science consistently. Material science, the investigation of issue and vitality, is an antiquated and wide field of science. 

The word 'material science' originates from the Greek 'information on nature,' and by and large, the field expects to break down and comprehend the characteristic wonders of the universe. 

One thing that may strike a chord when you consider material science is the numerous logical laws, which are articulations depicting wonders that have been over and over tried and affirmed. This is really a significant piece of material science. Physicists perform and rehash tests, in some cases relentlessly, to figure these laws and clarify how our universe functions. These laws, (for example, gravity and Newton's laws of movement) are so altogether tried that they are acknowledged as 'certainties,' and they can be utilized to assist us with anticipating how different things will act. 

Since material science clarifies normal marvels known to mankind, it's regularly viewed as the most key science. It gives a premise to every other science - without physical science, you were unable to have science, science, or whatever else!

History

Material science has been around for a long, long time. We believe the Ancient Greeks to be the 'authors' of early material science, as they pushed for a superior comprehension of the regular world around them. This incorporates some significant players you are likely acquainted with, similar to Socrates, Plato, and Aristotle. 

Current material science came hundreds of years after the fact, with people like Copernicus, Galileo, and Newton during the 15-and 1600s. There were numerous basic logical achievements during this time as individuals found increasingly more about our universe. 

Indeed, a great part of the information we underestimate was found during this Scientific Revolution. For instance, Copernicus was the first to show that the earth rotates around the sun, not the opposite way around. 

Galileo portrayed numerous major physical ideas, yet he additionally made numerous cosmic disclosures, for example, sunspots and planetary satellites, by idealizing the telescope. 

Material science surely wouldn't be the equivalent without Isaac Newton, who you will no uncertainty find out much about in your material science examines. He is likely generally popular for his three laws of movement and the law of widespread attraction. Newton is likewise credited with developing analytics, however you might possibly concur with that being something worth being thankful for!

Mechanics of Material Science 

Mechanics is commonly interpreted as meaning the investigation of the movement of articles (or their absence of movement) under the activity of given powers. Traditional mechanics is in some cases thought about a part of applied science. It comprises of kinematics, the depiction of movement, and elements, the investigation of the activity of powers in creating either movement or static harmony (the last establishing the study of statics). The twentieth century subjects of quantum mechanics, essential to treating the structure of issue, subatomic particles, superfluidity, superconductivity, neutron stars, and other significant marvels, and relativistic mechanics, significant when velocities approach that of light, are types of mechanics that will be examined later in this area. 

In traditional mechanics the laws are at first defined for point particles in which the measurements, shapes, and other characteristic properties of bodies are disregarded. Hence in the main estimate even articles as extensive as Earth and the Sun are treated as pointlike—e.g., in figuring planetary orbital movement. In inflexible body elements, the augmentation of bodies and their mass conveyances are considered also, however they are envisioned to be unequipped for disfigurement. The mechanics of deformable solids is versatility; hydrostatics and hydrodynamics treat, individually, liquids very still and moving. 

The three laws of movement set out by Isaac Newton structure the establishment of traditional mechanics, along with the acknowledgment that powers are coordinated amounts (vectors) and consolidate appropriately. The principal law, additionally called the law of latency, expresses that, except if followed up on by an outside power, an article very still stays very still, or if moving, it keeps on moving in an orderly fashion with steady speed. Uniform movement hence doesn't need a reason. Appropriately, mechanics focuses not on movement all things considered yet on the adjustment in the condition of movement of an item that outcomes from the net power following up on it. Newton's subsequent law compares the net power on an item to the pace of progress of its energy, the last being the result of the mass of a body and its speed. Newton's third law, that of activity and response, expresses that when two particles connect, the powers each applies on the other are equivalent in extent and inverse in bearing. Taken together, these mechanical laws on a fundamental level grant the assurance of things to come movements of a lot of particles, giving their condition of movement is known at some moment, just as the powers that demonstration among them and upon them from an external perspective. From this deterministic character of the laws of old style mechanics, significant (and likely off base) philosophical ends have been attracted the past and even applied to mankind's history. 

Lying at the most fundamental degree of material science, the laws of mechanics are described by certain balance properties, as exemplified in the previously mentioned balance among activity and response powers. Different balances, for example, the invariance (i.e., perpetual type) of the laws under reflections and turns did in space, inversion of time, or change to an alternate piece of room or to an alternate age of time, are available both in old style mechanics and in relativistic mechanics, and with specific limitations, likewise in quantum mechanics. The balance properties of the hypothesis can be appeared to have as numerical results fundamental standards known as protection laws, which attest the steadiness in season of the estimations of certain physical amounts under endorsed conditions. The preserved amounts are the most significant ones in material science; included among them are mass and vitality (in relativity hypothesis, mass and vitality are comparable and are moderated together), force, precise energy, and electric charge...

The Structure Of The World, History, Experimental Work, and World Map

 THE STRUCTURE OF WORLD 

HISTORY 

Man has always been interested to find how the world is structured. Long long ago scientists suggested that the world is made up of certain indivisible small particles. The number of the particles in the world is large but the varieties of particles are not may. Old Indian philosopher Kanadi derives his name from this proposition ( In Sanskrit or Hindi Kana means means a small particles ).

Experimental Work 

After extensive experimental work people arrived at the conclusion that the world is made up of just three types of ultimate particles, the proton, the neutron and the electron. All objects which we have around us, are aggregation of atoms and molecules. The molecules are composed of atoms and the atoms have at their heart a nucleus containing protons and neutrons. Electrons move around this nucleus in special arrangements. It is the number of protons, neutrons and electrons in an atoms that decide all the properties and behaviour of a material. Large number of atoms combine to from an object of moderate or large size. However, the laws that we generally deduce for these macroscopic objects are not always applicable to atoms, molecules, nuclei or the elementary particles These laws knows as classical physics deal with large size object only. When we say a particle in classical physics we mean an object which is small as compared to other moderate or large size object and for which the classical physics is valid. It may still contain millions and millions of atoms in it. Thus, a particle of dust dealt in classical physics may contain about 10^18 atoms.

IN 20 century 

20th century experiments have revealed another aspect of the construction of worlds. There are perhaps no ultimate indivisible particles. Hundreds of elementary particles have been discovered and there are free transformations from one such particle to the other. Nature is seen to be a well-connected entity.

World map 

What Is Time Travel, By Wormhole And Time Machine

 Time Travel

About Time Travel

Time travel — moving between various focuses in time — has been a famous theme for sci-fi for a considerable length of time. Establishments going from "Specialist Who" to "Star Trek" to "Back to the Future" have seen people get in a vehicle or the like and show up previously or future, prepared to take on new undertakings. Each accompany their own time travel hypotheses.

The truth, nonetheless, is more tangled. Not all researchers accept that time travel is conceivable. Some even say that an endeavor would be deadly to any human who decides to embrace it.

What Is Time ??

What is time? While the vast majority consider time a steady, physicist Albert Einstein demonstrated that time is a hallucination; it is relative — it can fluctuate for various eyewitnesses relying upon your speed through space. To Einstein, time is the "fourth measurement." Space is portrayed as a three-dimensional field, which furnishes a voyager with facilitates —, for example, length, width and stature — indicating area. Time gives another organize — course — albeit ordinarily, it just pushes ahead. (Alternately, another hypothesis declares that time is "real.Einstein's hypothesis of unique relativity says that time eases back down or accelerates relying upon how quick you move comparative with something different. Moving toward the speed of light, an individual inside a spaceship would age much more slow than his twin at home. Likewise, under Einstein's hypothesis of general relativity, gravity can twist time. 

Picture a four-dimensional texture called space-time. When anything that has mass sits on that bit of texture, it causes a dimple or a bowing of room time. The bowing of room time makes objects proceed onward a bended way and that shape of room is the thing that we know as gravity. 

Both the general and uncommon relativity hypotheses have been demonstrated with GPS satellite innovation that has exact watches ready. The impacts of gravity, just as the satellites' sped up over the Earth comparative with spectators on the ground, make the unadjusted tickers increase 38 microseconds per day. (Designers make alignments to represent the distinction.) 

As it were, this impact, called time widening, implies space explorers are time travelers, as they come back to Earth extremely, marginally more youthful than their indistinguishable twins that stay on the planet.

There are Many Way To Do Time Travel.

By The Wormhole!!

General relativity additionally gives situations that could permit explorers to return in time, as indicated by NASA. The conditions, nonetheless, may be hard to genuinely accomplish. 

One chance could be to go quicker than light, which goes at 186,282 miles for each second (299,792 kilometers for every second) in a vacuum. Einstein's conditions, however, show that an article at the speed of light would have both interminable mass and a length of 0. This seems, by all accounts, to be genuinely inconceivable, albeit a few researchers have broadened his conditions and said it may be finished. 

A connected chance, NASA expressed, is make "wormholes" between focuses in space-time. While Einstein's conditions accommodate them, they would crumple rapidly and would just be appropriate for little particles. Additionally, researchers haven't really watched these wormholes yet. Additionally, the innovation expected to make a wormhole is a long ways past anything we have today.

By Time Machine!!

It is commonly perceived that going ahead or back in time would require a gadget — a time machine — to take you there. Time machine research frequently includes twisting space-time so far that timetables betray themselves to frame a circle, actually known as a "shut time-like bend." 

To achieve this, time machines regularly are thought to require a fascinating type of issue with alleged "negative vitality thickness." Such intriguing issue has strange properties, remembering moving for the other way of ordinary issue when pushed. Such issue could hypothetically exist, however in the event that it did, it may be available just in amounts excessively little for the development of a time machine. 

Be that as it may, time-travel research recommends time machines are conceivable without outlandish issue. The work starts with a donut molded gap wrapped inside a circle of ordinary issue. Inside this donut molded vacuum, space-time could get twisted upon itself utilizing centered gravitational fields to shape a shut time-like bend. To return in time, an explorer would race around inside the donut, going further go into the past with each lap. This hypothesis has various obstructions, notwithstanding. The gravitational fields needed to make such a shut time-like bend would need to be exceptionally solid, and controlling them would need to be exact.

Planetary nebulae, discovery, and Properties

 Planetary nebulae

About

Planetary nebulae are cosmic articles made up basically of vaporous materials. They are stretched out in size and fluffy in appearance, and for the most part give some level of balance. The cloud is enlightened by a focal star, which at times is too swoon to even think about being seen. Albeit at first gathered with cosmic systems and star bunches under the class of "nebulae", we currently realize that universes and star groups are comprised of stars, while planetary nebulae are vaporous.

 

Planetary nebulae were found by stargazers as right on time as the eighteenth century, with four planetary nebulae being remembered for the inventory of nebulae by Charles Messier in 1784. The most notable planetary cloud is the Ring Nebula in the star grouping of Lyra (Figure 1), which can undoubtedly be seen with a little telescope in summer from the Northern side of the equator. The expression "planetary nebulae" was authored by William Herschel for their clear likeness to the greenish plates of planets, for example, Uranus and Neptune. This ended up being a lamentable misnomer as planetary nebulae have nothing to do with planets.

Discovery and Distribution of planetary nebulae

Planetary nebulae are normally one light year across and are growing at a pace of around 20-50 km for every second. The thickness in the nebulae is extremely low, running from a few hundred to a million iotas for each cubic centimeter. Such conditions are better than any vacuum one can accomplish on Earth. The temperature of the gas in the cloud is around 10,000 degrees Celsius, and the focal stars of planetary nebulae are among the most smoking stars in the Universe, with temperature in the scope of 25,000 to more than 200,000 degrees Celsius. The focal stars are additionally exceptionally brilliant, typically hundreds to thousands of times more radiant than the Sun. In any case, as a result of their high temperatures, they transmit principally in the bright and are regularly black out in noticeable light.

 

The spectra of planetary nebulae are generally not quite the same as those of stars. Rather than a consistent shading from red to blue as on account of the Sun, the spectra of planetary nebulae are ruled by discrete emanation lines produced by particles and particles. In contrast to stars, whose nonstop spectra give them a composite white appearance, planetary nebulae have a rich assortment of hues. A few instances of solid outflow lines are the red line of hydrogen and the green line of doubly ionized oxygen (O++). These brilliant emanation lines are fueled by the focal star, which is the wellspring of vitality for the whole cloud. Bright light discharged by the focal star is blocked by iotas in the cloud and changed over to noticeable line radiation. First the bright light eliminates electrons from the iota (in a cycle called photoionization). The liberated electrons at that point either recombine with the particle and emanate a recombination line, or crash into different iotas and particles to cause the discharge of a collisionally energized line. As a result of the low thickness conditions, nuclear lines that are commonly stifled under high thickness conditions as in the research facility on earth however which can be created in the low thickness states of planetary nebulae. These "taboo lines" (of which the oxygen green line is a model) are exceptionally unmistakable in planetary nebulae, making them ideal research facilities to examine nuclear material science (Aller 1991).

 

Planetary nebulae are among the not many classes of heavenly articles that transmit unequivocally all through the electromagnetic range from radio to X-beam. Radio continuum radiation is discharged by the ionized gas segment of the nebulae. The atomic and strong state segments add to radiations in the infrared and submillimeter-wave areas (see segment beneath). The optical locale is overwhelmed by nuclear line outflows from ionized gas. A million-degree air pocket of amazingly low-thickness gas made by the cooperating winds measure produces discharges in the X-beam.

 

 Properties of planetary nebula

Planetary nebulae are generally recognized by their outflow line range. Latest revelations of new planetary nebulae are the consequence of imaging studies of the Galaxy utilizing a limited band channel around the Hα line of hydrogen (Parker et al. 2006). This permits outflow nebulae to be effortlessly isolated from stars. There are roughly 2,500 planetary nebulae classified in the Milky Way Galaxy, but since of obscuration of galactic residue and inadequacy of studies, the complete populace is required to be around multiple times this number. Because of ghastly similitudes, planetary nebulae can be mistaken for other discharge line articles, for example, HII locales (nebulae related with youthful stars), advantageous stars or novae (both are aftereffects of paired star development). Most planetary nebulae in the Milky Way Galaxy are disseminated around the Galactic plane, as their begetters dive from a halfway mass heavenly populace.

 

Since the light from planetary nebulae is amassed in discharge lines, they can be effortlessly recognized from stars even in systems far away. A huge number of planetary nebulae have now been listed in outside universes as distant as 100 million light years away. Planetary nebulae have been widely utilized as standard candles to decide the age and size of the Universe (Jacoby 1989). By following the speed examples of planetary nebulae in worlds, space experts can likewise delineate the circulation of dim issue in cosmic systems.

 

What is Bonds Ionic and Covalent Bonds simple Explanation

 Bonds 

The atoms form molecules primarily due to the electrostatic interaction between the electrons and the nuclei. These interactions are described in terms of different kinds of bonds. We shall briefly discuss two important bonds that frequently occur in materials.

Ionic Bond

In an ionic bond two atoms come close to each other and an electron is completely transferred from one atom to the other. This leaves the first atom positively charge and the other one negatively charged. There is an electrostatic attraction between the ions which keeps them bound. For example, when a sodium atom comes close to a chlorine atom, an electron of the sodium atom is completely transferred to the chlorine atom. The positively charge sodium ion and the negatively charged chlorine ion attract each other to form an ionic bond resulting in sodium chloride molecule.

Covalent Bond 

In many of the cases a complete transfer of electron from one atom to another does not take place to forma bond. Rather, electrons from neighbouring atoms are made available for sharing between the atoms. Such bonds are called covalent bond. When two hydrogen atoms come close to each other, both the electrons are available to both the nuclei. In other words, each electron moves through the total space occupied by the two atoms. Each  electrons is pulled by both the nuclei. Chlorine molecule is also formed by this mechanism. Two chlorine atoms share a pair of electrons to form the bond. Another example of covalent bond is hydrogen chloride (HCL) Molecule.

Three States Of Matter Examples In Physics

Three States Of Matter 

If two molecules are kept at a separation r = r。,  they will stay in equilibrium. If they are slightly pulled apart so that r > r。 , an attractive force will operate between them. If they are slightly pushed so that r < r。, a repulsive force will operate. Thus, if a molecule is slightly displaced from its equilibrium position, it will oscillate about its mean position. This is the situation in a solid. The molecules are close to each other, very nearly at the equilibrium separations. The amplitude of vibration is very small and the molecules remain almost fixed at their positions. This explains why a solid has a fixed shape if no external force act to deform it.

In liquids, the average separation between the molecules is somewhat large. The attractive force is weak and the molecules are more free to move inside the whole mass of the liquid. In gases, the separation is much larger and the molecular force is very weak.

(1). Solid State

In solids, the intermolecular forces are so strong that the molecules or ions remain  almost fixed at their equilibrium positions. Quite often these equilibrium positions have a very regular three-dimensional arrangement which we call crystal. The positions occupied by the molecules or the ions are called lattice points. Because of this long range ordering, the molecules or ions combine to form large rigid solids.

The crystalline solids are divided into four categories depending on the nature of nature of the bonding between the basic units.

(2). Molecular Solid 

In a molecular solid, the molecules are formed due to covalent bonds between the atoms. The bonding between the molecules depends on whether the molecules are polar or nonpolar as discussed below. If the centre of negative charge in a molecule coincides with the centre of the positive charge, the molecule is called nonpolar. Molecules of hydrogen, oxygen, chlorine, etc., are of this type. Otherwise, the molecule is called a polar molecule. Water molecule is polar. The bond between polar molecules is called a dipole-dipole bond. The bond between nonpolar molecules is called a van der Waals bond. Molecular solids are usually soft and have low melting point. They are poor conductors of electricity.

(a). Ionic Solid

In an ionic solid, the lattice points are occupied by positive and negative ions. The electrostatic attraction between these ions binds the solid. These attraction force are quite strong so that the material is usually hard and has fairly high melting point. they are poor conductors of electricity.

(b).Covalent Solid 

In a covalent solid, atoms are arranged in the crystalline form. The neighbouring atoms are bound by shared electrons. Such covalent bonds extend in space so as to form a large solid structure. Diamond, silicon, etc., are examples of covalent solids. Each carbon atom is bonded to four neighbouring carbon atoms in a diamond structure. They are quite hard, have high melting point and are poor conductors of electricity.

(c). Metallic Solid

In a metallic solid, positive ions are situated at the lattice points. These ions are formed by detaching one or more electrons from the constituent atoms. These electrons are highly mobile and move throughout the solid just like a gas. They are very good conductors of electricity.

(3). Amorphous or Glassy State

There are several solids which do not exhibit a long range ordering. However, they still show a local ordering so that some molecules (say 4-5) are bonded together to form a structure. Such independent units are randomly arranged to form the extended solid. In this respect the amorphous solid is similar to a liquid which also lacks any long range ordering. However, the intermolecular force in amorphous solids are much stronger than those in liquids. This prevents the amorphous solids to flow like a fluid. A typical example is glass made of silicon and oxygen together with some other elements like calcium and sodium. The structure contains strong Si-O-Si bonds, but the structure does not extend too far in space.

The amorphous solids do not have a well-defined melting point. Different bonds have different strengths and as the material is heated the weaker bonds break earlier starting the melting process. The stronger bonds break at higher temperatures to complete the melting process.

DEFINITION OF BASE UNITS, Metre, Kilogram, Second, Ampere, Kelvin, Mole, Candela

 UNITS

Physics describes the law of nature. This description is quantitative and involves measurement and comparison of physical quantities. To measure a physical quantity we need some standard unit of that quantity.

Who Decides the Units ?

How is a standard unit chosen for a physical quantity ? The first thing is that it should have international acceptance. Otherwise, everyone will choose his or her own unit for the quantity and it will be difficult to communicate freely among the persons distributed over the world. A body named Conference Generale des poids et Mesures or CGPM also known as General Conference on Weight and Measures  English has been given the authority to decide the units by international agreement. It holds its meetings and any changes in standard units are communicated through the publications of the conference.

Definitions Of Base Units

Any standard unit should have the following two properties :

(a) Invariability : The standard unit must be invariable. Thus, defining distance between the tip of the middle finger and the elbow as a unit of length is not invariable.

(b) Availability : The standard unit should be easily made available for comparing with other quantities.

The procedures to define a standard value as a unit are quite often not very simple and use modern equipments. Thus, a complete understanding of these procedures cannot be given in the first chapter. We briefly mention the definitions of the base units which may serve as a reference if needed.

Metre

It is the unit of length. the distance travelled by light in vacuum in 1/299,792,458 second is called 1 m. 

Kilogram 

The mass of a cylinder made of platinum-iridium alloy kept at International Bureau of Weights and Measures is defined as 1 kg.

Second

Cesium-133 atom emits electromagnetic radiation of several wavelengths. A particular radiation is selected which corresponds to the transition between the two hyperfine levels of the ground state of Cs-133. Each radiation has a time period of repetition of certain characteristics. The time duration in 9,192,631,770 time periods of the selected transition is defined as 1 s.

Ampere

Suppose two long straight wires with negligible cross-section are placed parallel to each other in vacuum at a separation of 1 m and electric currents are established in the two in same direction. The wires attract each other. If equal currents are maintained in the two wires so that the force between them is 2 ｘ 10^-7  newton per metre of the wires, the current in any of the wires is called 1 A. Here, newton is the SI unit of force.

Kelvin

The fraction 1/273.16 of the thermodynamic temperature of triple point of water is called 1K.

Mole

The amount of a substance that contains as many elementary entities (molecules or atoms if the substance is monatomic) as there are number of atoms in 0.012 kg of carbon-12 is called a mole. This number (number of atoms in 0.012 kg of carbon-12) is called Avogadro constant and its best value available is 6.022045 ｘ 10 ^23 with an uncertainty of about 0.000031 ｘ 10^23 .

Candela

The SI unit of luminous intensity is 1 cd which is the luminous intensity of a blackbody of surface area 1/600,000 m^2 placed at the temperature of freezing platinum and at a pressure of 101,325 N/m^2 , in the direction perpendicular to its surface.

TWIN PARADOX REAL LIFE SIMPLE EXPLANATION

 Twin Paradox Real Life Simple Explanation 

As the postulates of special relativity lead to result which contradict 'common sense' a number of interesting paradoxes have been floated. We shall describe one of the most famous paradoxes of relativity- the twin paradox. consider the twins Ram and Balram living happily on the earth. Ram decides to make a trip to a distant planet p, which is at rest with respect to the earth, and come back. He boards a spaceship S1, going toward the planet with a uniform velocity. When he reaches the planet, he jumps from the spaceship S1 to another spaceship S1 which is going toward the earth. When he reaches the earth, he jump out and meets his brother Balram. 

As Ram returns from his trip and stands next to Balram, do they have equal age ? Or is Ram younger than Balram or is he older than Balram ?

To keep the calculation simple, let us assume the following date:

Distance between the earth and the planet = 8 light-years,

speed of S1 with respect to earth = 0.8c, and speed of S2 with respect to earth = 0.8c.

When we said that the distance between the earth and the planet P is 8 light-years, was it clear to you that this length is the length as measured from the earth frame ?

First, let us analyse the events from the point of view of Balram who is on the earth. For him, both the spaceships move at a speed 0.8c. So,

γ = 1/√1-v^2/c^2 = 1/0.6 . 

When Ram is on S1, he is moving and all his clocks run slower because of time dilation. His heartbeat, pulse beat, etc., represent clocks in themselves and they all run slower. Balram calculates that Ram will take 8 light-year/0.8c = 10 years to reach the planet P. But during all these 10 years, time is passing slowly on S1 and the clock will read only 10 yearsｘ 0.6 = 6 years in this period. The number of breaths taken by Ram corresponds to 6 years only.

Ram jumped into S2 for the return journey. This spaceship is also moving at 0.8c and for Balram , time passes slowly on S2 as well. Although 10 years passed on the earth during Ram's return journey, on the spaceship the journey was clocked at 6 years. Thus, Ram has aged only 12 years whereas Balram has aged 20 years during this expedition. Ram has become younger than Balram by 8 years. This difference in aging is real in the sense that Ram shows lesser signs of aging like he has lesser white hairs than his brother.

The observation of Balram is quite consistent with the special theory of relativity. Such experiment are indeed performed in laboratories with radioactive particles. particles are accelerated to large speed and are kept at these speed for quite some time by magnetic fields. These particles with large speeds have longer lives than their counterparts kept at rest in the laboratory.

The paradox arises when we analyse the events from the point of veiw of Ram. When he is in the spaceship S1, to him the distance between the earth and the planet is not 8 light-years. The earth and the planet P  are moving with respect to Ram and hence he is measuring contracted length. The separation is, therefore, 8 light-years ｘ0.6 = 4.8 light-years. As the planet is approaching Ram at 0.8c, the taken by the planet to reach Ram is 4.8 light-year/0.8c = 6 years. So according to Ram's clock, he jumped from S1 to S2 6 years after getting into S1. Once he is on S2, the earth and the planet are again moving with the same speed 0.8 Again, the earth is 4.8 light-years from the planet and is approaching at 0.8c. It takes 6 years for the earth to reach Ram. Thus, according to Ram's clock, he was out for 12 years from the earth, the same result as Balram had expected.

But how about Ram's calculation of Balram's age ? When Ram is on S1, the earth is going away from him with a speed 0.8c. Ram will find that the time on the earth is passing slower by a factor of 0.6 so that Balram is again slower than he is. The same is true when he is on S2. During this period also,  Balram is moving (toward Ram) with a speed 0.8c and hence time is passing slowly for Balram. As 12 years passes on Ram's clock, he calculates that Balram's clocks have advanced only by 12 years ｘ0.6 = 7.2 years in this period, According to this analysis, Ram should find that Balram is 12 - 7.2 = 4.8 years younger than him. 

This is the paradox. According to Ram, Balram's clocks are running slow and according to Balram, Ram's clock are running slow. Each thinks the other is younger. Where lies the fallacy ?

The fallacy lies in the fact that Ram has changed frames whereas Balram has stayed in an inertial frame. Thus, the roles of the twins are not symmetrical. The ordering of events are different in different frames and Ram must take that into account when he changes frames. Suppose Ram gets into the spaceship S1 when his clock reads zero. So does Balram's clock. What is the reading of the planet's clock at this instant ? According to Balram, it is zero because both the earth and the planet are at rest and the clock are synchronized in his frame. But that is not so in S1. As Ram gets into S1, he may have the following conversation with the captain of the ship. 

Captain: Welcome aboard S1. I saw you on the earth, coming toward us. Your jump to board this ship was perfect. Where are you going ?

Ram: Thank you. I am going to the planet P . How far is it from here and how long will it take for the planet to come to us ?

Captain: Planet P is 4.8 light-years from  us at the moment. It is coming toward us at a speed of 0.8c so it will take 4.8 light-years/0.8c= 6 years for the planet P to reach us.

Ram: Well the clock on the earth and the planet are running a bit slower than ours. I have been taught that moving clock run slow by a factor of γ. This factor is 1/0.6 for these clocks. So they will advance by 6 years ｘ0.6 = 3.6 years by the time the planet reaches us.

Captain: Yes, both the clock will advance by 3.6 years by the time you jump on the planet P.

Ram: The earth-clock was reading t = 0 as we passed the earth. This means when I jump on the planet P the clocks on the earth and the planet will be reading 3.6 years.

Captain: Here you are mistaken. Don't you remember that the planet's clock is not synchronized with the earth's clock ? The planet's clock is at the rear end, and hence is running 6.4 years ahead of the earth's clock. At the instant the earth's clock was reading zero, the planet's clock was reading 6.4 years. As the planet reaches us, both the clocks will advance by 3.6 years. So when you jump out of S1, the earth's clock will be reading 3.6 years but the planet's clock will be reading 10 years.

Ram understands the logic. In the earth's frame the two clocks read zero simultaneously. But in S1-frame, the event ''planet's clock reading zero'' occurred several years before '' earth's clock reading zero''. Six years pass in S1 and Ram finds that the planet P has reached him. He finds another spaceship S2 which is heading towards the earth. Ram jumps onto S2. In the process he looks at the planet's clock and finds that it is reading 10 years as calculated by him on S1. On S2, he starts talking to the commander of the ship.

Commander: Welcome to S2. How long will you be with us ? 

Ram: Thank you. I am going to Earth. Earth is at present 4.8 light-years from here and is coming toward us with a speed of 0.8c. So I will be with you for 6 years. The captain of S1 told me that the earth's clock is reading 3.6 years at this moment whereas the planet's clock reads 10 years. There is a difference of 6.4 years in the reading because the two clock are not synchronized. Also....

Commander: Sorry for interrupting you, but you are mistaken. It is true that the earth's clock and the planet's clock are not synchronized as they are moving past us. Also the difference in the reading of the two clocks is 6.4 years. But the planet's clock is at the front and the earth's clock is at the rear. It is the earth's clock that is leading by 6.4 years. At the moment the planet's clock reads 10 years and hence the earth's clock must be reading 16.4 years.

Ram: hmm... you are right. In S1, the earth was at the front and its clock lagged behind the planet's clock. But in S2 it is the other way round. Indeed the earth's clock reads 16.4 years whereas the planet's clock reads 10 years.

Commander: That's right. The earth's clock is reading 16.4 years at present. It will advance by another by another 3.6 years during the 6 years you will be with us. So it will be reading 20 years when the earth reaches you.

We see that the paradox is resolved.

ATMOSPHERIC ELECTRICITY IN PHYSICS FULL INFORMATION

 Atmospheric electricity in Physics Full Information 

The earth and the atmosphere surrounding it show very interesting electric phenomena. The earth has a negative charge spread with approximately uniform density over its surface. The average surface charge density on the earth is little less than one nanocoulomb per square metre. There is a corresponding electric field of about 100Vm^-1 in the atmosphere above the earth. This field is in the vertically downward direction. This means, if you look at a flat desert, the electric potential increases by about 100 V as you move up by 1 m. The potential keeps on increasing as one goes higher in atmosphere but the magnitude of the electric field gradually decreases. At about 50 km from the earth's surface, the field is negligible. The total potential difference between the earth's surface and the top of the atmosphere is about 400 kV.

The atmosphere contains a number of ions, both positively charge and negatively charged. The main source of these ions is cosmic rays which come from outside the earth, even from outside the solar system. These rays come down to the earth and ionize molecules in the air. Air contains dust particles which become charged by friction as they move through the air. This is another source of the presence of charged ions in air. Because of the electric field in the atmosphere, positive ions come down and negative ions go up. Thus, there is an electric current in the atmosphere. This current is about 3.5 ｘ10^-12 A over a square metre area parallel to the earth's surface. When the total surface area of the earth is considered, 1800 A of current reaches the earth.

The density of ions increases with height over the earth;s surface. Also, the density of air decreases and the ions can travel larger distance between collisions. Both these factors contribute to the fact that ''conductivity of air'' increases with altitude. At about 50 km above the earth's surface, the become highly conducting. We can draw an equivalent picture by assuming that at about this height there is a perfectly conducting surface having a potential of 400 kV and current comes down from this surface to the earth.

If 1800 A of current flows towards the earth, the entire negative charge of the earth should get neutralised in about half an hour and the electric field in the atmosphere should reduce to zero. But it is not so. So, there must be some mechanism which brings negative charge back to the earth, so that the 400 kV potential difference is maintained. This situation is like that of a battery. The current provided by a battery discharges it. There is a source of emf which maintains the potential difference across the battery's terminals. So, what is the source that charge our atmospheric battery. The answer is thunderstorms and lighting. 

Because of  the difference in temperature and pressure between different parts of the atmosphere, air packets keep on moving in a rather systematic fashion. As the upper atmosphere is cool (temperature is around -10 ℃ at a height of 3-4 km and -20℃ at a height of 6-7 km ), water vapour condenses to form small water droplets and tiny ice particles. A parcel of air with these droplets and ice particles forms a thunderstorm. A typical thunderstorm may have an average horizontal extension of about 7-8 km and a vertical extension of about 3 km. A matured thunderstorm is formed with its lower end at a height of about 3-4 km above the earth's surface and the upper end at about 6-7 km above the earth's surface. 

The upper part of a thunderstorm contains excess positive charge and the lower part contains excess negative charge. The density of negative charge in the clouds in the lower part of the storm is very high. This negative charge created a potential difference of 20 to 100 MV between these clouds and earth. Note that this potential difference is much larger than the 400 kV between the earth and the top of atmosphere and is opposite in sing.