Saturday, 9 September 2017

What is relativity all about? 🌡

Our principal focus of relativity has to do with measurements of events where and when they happen, and by how much any two events are separated in space and in time. In addition, relativity has to do with transforming such measurements and others between reference frames that move relative to each other (Hence the name relativity).

Transformations and moving reference frames were well understood and quite routine to physicists in 1905. Then Albert Einstein published his special theory of relativity. The adjective special means that the theory deals only with inertial reference frames, which are frames in which Newton's laws are valid. This means that the fames do not accelerate; instead they can move only at constant velocities relative to one another. (Einstein's general theory of relativity treats the more challenging situation in which reference frames accelerate; the term relativity implies only inertial reference frames.)

Starting with two deceivingly simple postulates, Einstein stunned the scientific world by showing that the old ideas about relativity were wrong, even though everyone was so accustomed to them that they seemed to be unquestionable common sense. This supposed common sense, however, was derived from experience only with things that move rather slowly. Einstein's relativity, which turns out to be correct for all possible speeds, predicted many effects that were, at first study, bizarre because no one had experienced them. 

In particular, Einstein demonstrated that space and time are entangled that is, the time between two events depends on how far apart they occur, and vice versa. Also, the entanglement is different for observers who move relative to each other One result is that time does not pass at a fixed rate, as if it were ticked off with mechanical regularity on some master grandfather clock that controls the universe. Rather, that rate is adjustable: Relative motion can change the rate at which time passes. Prior to 1905, no one but a few daydreamers would have thought that. Now engineers and scientists take it for granted because their experience with special relativity has reshaped their common sense. Special relativity has the reputation of being difficult. It is not difficult mathematically, at least not here. However, it is difficult in that we must be very careful about who measures what about an event and just how that measurement is made and it can be difficult because it can contradict experience.

Friday, 8 September 2017

Mechanism of a nuclear reactor ☠

For large-scale energy release due to fission, one fission event must trigger others, so that the process spreads throughout the nuclear fuel like flame through a log. The fact that more neutrons are produced in fission than are consumed raises the possibility of just such a chain reaction, with each neutron that is produced potentially triggering another fission. The reaction can be either rapid (as in a nuclear bomb) or controlled (as in a nuclear reactor). Suppose that we wish to design a reactor based on the fission of 25U by thermal neutrons. Natural uranium contains 0.7% of this isotope, the remaining 99.3% being 2MU, which is not fissionable by thermal neutrons, Let us give ourselves an edge by artificially enriching the uranium fuel so that it contains perhaps 3% 215U. Three difficulties still stand in the way of a working reactor.

 Some of the neutrons produced by fission will leak out of the reactor and so not be part of the chain reacting Leakage is surface effect; its magnitude is proportional to the square of pical reactor dimension (the surface area of a cube of edge length a is 6a^2). Neutron production, however, occurs throughout the volume of the fuel and is thus proportional to the cube of a typical dimension (the volume of the same cube is a). We can make the fraction of neutrons lost by leakage as small as we wish by making the reactor core large enough, thereby reducing the surface-to-volume ratio.

The neutrons produced by fission are fast, with kinetic energies of about 2 MeV. However, fission is induced most effectively by thermal neutrons. The fast neutrons can be slowed down by mixing the uranium fuel with a substance-called a moderator that has two properties: It is effective in slowing down neutrons via elastic collisions, and it does not remove neutrons from the core by absorbing them so that they do not asult in fission. Most power reactors in North America use water as a modern hydrogen nuclei (protons) in the water are the effective component, if a moving particle has a head on elastic collision with a stationary particle, the moving particle loses all its kinetic energy if the two particles have the same mass. Thus, protons form an effective moderator because they have approximately the same mass as the fast neutrons whose speed we wish to reduce.

 As the fast (2 MeV) neutrons generated by fission are slowed down in the moderator to thermal energies (about 0.04 eV), they must pass through a critical energy interval (from to 100 ev) in which they are particularly susceptible to nonfission capture by 2U nuclei. Such resonance capture, which results in the emission of a gamma ray, removes the neutron from the fission chain. To minimize such nonfission capture, the uranium fuel and the moderator are not intimately mixed but are “clumped together," occupying different regions of the reactor volume in a typical reactor. The uranium fuel is in the form of uranium oxide pellets which are inserted end to end into long hollow metal tubes. The liquid moderator surrounds bundles of these fuel rods, forming the reactor core. This geometric arrangement increases the probability that a fast neutron, produced in a fuel rod will find itself in the moderator when it passes through the critical energy interval. Once the neutron has reached thermal energies, it may still be captured in ways that do not result in fission (called thermal capture) However, it is much more back into a fuel rod and produce likely that the thermal neutron will wander fission event. Neutron balance in a typical power reactor operating at constant power.

Let us trace a sample of 1000 thermal neutron through one complete eycle, or generation, in the reactor core. They produce 1330 neutrons by fission in the 2SU fuel and 40 neutrons by fast fission in 3*U, which gives 370 neutrons more than the original 1000, all of them fast. When the reactor is operating at a steady power level, exactly the same number of neutrons (370) is then lost by leakage from the core and by nonfission capture, leaving 1000 thermal neutrons to start the next generation. In this cycle, of course, each of the 370 neutrons produced by fission events represents a deposit of energy in the reactor core, heating up the core. The mutiplication factor k an important reactor parameter is the ratio of the number of neutrons present at the beginning of a particular generation to the number present at the beginning of the next generation. The multiplication factor is 1000/ 1000, or exactly unity. For k = 1, the operation of the reactor is said to be exactly critical, which is what we wish it to be for steady power operation. Reactors are actually designed so that they are inherently supercritical K > 1; the multiplication factor is then adjusted to critical operation by inserting control rods into the reactor core. These rods, containing a material such as cadmium that absorbs neutrons readily, can be inserted farther to reduce the operating power level and withdrawn to increase the power level or to compensate for the tendency of reactors to go suberitical as (neutron-absorbing) fission products build up in the core during continued operation. If you pulled out one of the control rods rapidly, how fast would the reactor power level increase? This response time is controlled by the fascinating circumstance that a small fraction of the neutrons generated by fission do not escape promptly from the newly formed fission fragments but are emitted from these fragments later, as the fragments decay by beta emission. Of the 370 "new" neutrons produced in, for example, perhaps 16 are delayed. Being emitted from fragments following beta decays whose half-lives range from 0.2 to 55 s. These delayed neutrons are few in number, but they serve the essential purpose of slowing the reactor response time to match practical mechanical reaction time to shows the broad outlines of an electric power plant based on pressurized water reactar (PWR). A type in common use in North America. In such a reactor, water is used both as the moderator and as the heat transfer medium. In the primary loop, water is circulated through the reactor vessel and transfers energy at high temperature and pressure (possibly 600 K and 150 atm) from the hot reactor core to the steam generator, which is part of the secondary loop. In the steam generator, evaporation provides high-pressure steam to operate the turbine that drives the electric generator.

To complete the secondary loop, low pressure steam from the turbine is cooled and condensed to water and forced back into the steam generator by a pump. To give some idea of scale, a typical reactor vessel for a 1000 MW (electric) plant may be 12 m high and weigh 4 MN. Water flows through the primary loop at a rate of about I ML/min. An unavoidable feature of reactor operation is the accumulation of radioactive wastes, including both fission products and heavy transuranic nuclides such as plutonium and americium. One measure of their radioactivity is the rate at which they release energy in thermal form shows the thermal power generated by such wastes from one year's operation of a typical large nuclear plant. Note that both scales are logarithmic. Most "spent" fuel rods from power reactor operation are stored on site, immersed in water: permanent secure storage facilities for reactor have to be completed much weapons derived radioactive waste accumulated during Warld War Il and in subsequent years is also still in on site storage. For example, shows an underground storage tank farm under construction at the Hanford Site in Washington State; each large tank holds 1 ML of highly radioactive liquid waste. There are now 152 such tanks at the site, in addition, much solid waste, both low-level radioactive waste and high-level waste (reactor cores from decommissioned nuclear submarines, for example) is buried in trenches.

Wednesday, 6 September 2017

What should be the cause of death of sun forming into red giant?

The Sun radiates energy at the rate of 3.9 x 108 W and has been doing so for several billion years. Where does all this energy come from? Chemical burning is ruled out; if the Sun had been made of coal and oxygen-in the right proportions for combustion-it would have lasted for only about 1000 y. Another possibility is that the Sun is slowly shrinking, under the action of its own gravitational forces. By transferring gravitational potential energy to thermal energy, the Sun might maintain its temperature and continue to radiate. Calculation shows, however, that this mechanism also fails; it produces a solar lifetime that is too short by a factor of at least 500 that leaves only thermonuclear fusion. The Sun, as you will see, burns not coal but hydrogen, and in a nuclear furnace, not an atomic or chemical one. The fusion reaction in the Sun is a multistep process in which hydrogen is burned into helium, hydrogen being the "fuel and helium the "ashes."

The p-p cycle starts with the collision of two protons ('HH) to form deuteron (H), with the simultaneous creation of a positron (e) and a neutrino. The positron very quickly encounters a free electron (e) in the Sun and both particles annihilate their mass energy appearing as two gamma-ray photons. A pair which is actually extremely rare. In fact, only once in about 1028 proton-proton collisions is deuteron formed: in the vast majority of cases, the two protons simply rebound elastically from each other. It is the slowness of this "bottleneck" process that regulates the rate of energy production and keeps the Sun from exploding. In spite of this slowness, there are so very many protons in the huge and dense volume of the Sun's core that deuterium is produced in just this way at the rate of 1012 kg/s.

Once a deuteron has been produced, it quickly collides with another proton and forms a He nucleus. Two such 'He muclei may eventually (within 10 y: there is plenty of time) find each other, forming an alpha particle He and two protons,  Overall the p-p cycle amounts to the combination of four protons and two electrons to form an alpha particle, two neutrinos, and six gamma-ray photons. obtaining the quantities in the two sets of parentheses then represent atoms of bydrogen and of helium. That allows us to compute the energy release in the overall reactions.

About 05 MeV of this energy is carried out of the Sun by the two neutrinos is deposited in the core of the Sun as thermal energy. That thermal energy is then gradually transported to the Sun's surface where it is radiated away from the Sun as electromagnetic waves, including visible light.

Hydrogen burning has been going on in the Sun for about 5 x 108 y, and calculations show that there is enough hydrogen left to keep the Sun going for about the same length of time into the future. In 5 billion years, however, the Sun's which by that time will be largely helium, will begin to cool and the Sun will to collapes under its own gravity. This will raise the core temperature and cause the outer envelope to expand, turning the Sun into what is called a red ziant. If the core temperature increases to about 10 K again, energy can be produced through fusion once more this time by burning helium to make carbon. As a star evolves further and becomes still hotter, other elements can be formed by other fusion reactions However, elements more massive than those near the peak of the bindinig energy cannot be produced by further fusion processes.

Elements with mass numbers beyond the peak of that curve are thought to be formed by neutron capture during cataclysmic stellar explosions that we call super
novas. In such an event the outer shell of the star is blown outward into space, where it mixes with and becomes part of the tenuous medium that tils the space between the stars. It is from this medium, continually enriched by debris from stellar explosions, that new stars form, by condensation under the influence of the gravitational force. The abundance on Earth of elements heavier than hydrogen and helium suggests that our solar system has condensed out of interstellar material that contained remnants of such explosions. Thus, all the elements around us including those our own body were manufactured in the interios of stars that no longer exist as one scientist put it "In truth we are the children of the stars

Tuesday, 5 September 2017

How to solve the constant acceleration equation problems easily?

In many types of motion, the acceleration is either constant or approximately so. For example, you might accelerate a car at an approximately constant rate when a traffic light turns from red to green. Later when you brake the car to a stop, the deceleration might also be approximately constant. Such cases are so common that a special set of equations has been derived for dealing with them. when you work on the homework problems, keep in mind that equations are valid only for constant acceleration or situations in which you can approximate the acceleration as being constant, When the acceleration is constant, the average acceleration and instantaneous acceleration are equal.

basic equations for constant acceleration; they can be used to solve any constant acceleration problem. However, we can derive other equations that might prove useful in certain specific situations. First, note that five quantities can possibly be involved in any problem regarding constant acceleration namely, x-x0, v, t, a, and v0. Usually, one of these quantities is not involved in the problem, either as a given or as an unknown. We are then presented with three of the remaining quantities and asked to find the fourth.

Constant acceleration problem

lists of basic constant acceleration equations as well as the specialized equations to solve a simple constant acceleration problem. you can usually use an equation from this list.

Thursday, 15 June 2017

Why is there a validity for data packs?

As you know before Vodafone net pack, Airtel data plan, BSNL data plan cost around 300 rupees to 500 rupees only for 28 days. But have you ever imagine why 28 days or not 30 days and why limitation to 1 month. So here is a simple answer of this burning question.

The maximum validity of data plans should not reach 90 days in total rule set by TRAI (Telecom regulatory Authority of India) but now they updated the rule and exceed the time limit to 365 days (jio-jio).

Now why 2 days less than 30 days of a month i.e. 28 days. So if it is 30 days we have to recharge 12 times a year but if it is 28 days we have to recharge 13 times a year so that's the business and so that Telecom operator can earn more as that simple.

Mobile data plans

There is one more tweak if it is 28 days then you will remember or prepared for recharging before 1 day of the next month but if it is 30 days then date maths get complicated and you forget to recharge and your balance hits the magical zero now there is a no tension because "jio maine leli aaj ,jio maine leli ajj"πŸ˜‚

Now why is there not a validity for lifetime so there is a simple reason because there is a very less number of wired broadband connection and WiFi at homes in India. People are much more depend on data plans as a result cause more and more traffic to a single bandwidth and Spectrum results in spectrum crunch. This can be understand by the fact that in daytime jio speed is less due to heavy traffic in a particular area but at night the speed is usually better than days.
For data packs to be unlimited we have to install more than more wired broadband connections and public hotspots.

On 1 April 2005, NASA pulled a prank telling the world, that they have found water on Mars 😚

Tuesday, 13 June 2017

Why are bikes always have their headlights on in India?

Now a days in India many people wonders to see headlamp of bikes on in day time and fly their hands high to tell the person in order to kindly switch off the headlights of the bike. But they don't know that government of India introduced AHO (automatic headlights on) norms in all new bikes and Scotties (yup Scotties also 😎) for the safety of riders and the people on the roads.
Now come to the point what does AHO  means? and Why is it introduced?

So let's get started.....

What does AHO means?

Bikes headlights is on always in india

AHO stands for automatic headlights on. It is a norm implemented by government of India made it compulsory that new bikes will have headlights on all the time, be it day or night. When two wheelers have this feature their headlights will start glowing as the engine is started and they won't have any switch to turn on & off the headlights.

Why is it introduced?

Basically AHO introduced for the safety of the riders and for the people on the roads. DRL(day time running lights terms used in European countries like AHO in India) was introduced in Europe in 2003 because of low visibility in the climate. In most part of the europe climate is cloudy, foggy, always raining and snowing. This makes lower visibility for the riders causes accidents on the roads. In India, drivers claim that they didn't see the motorcycles due to lower lighting, fog, heavy rain and because of bikes are very narrow. Hence govt. Of India introduced AHO feature in all two-wheelers from April onwards.

It will take some time to digest this fact of AHO. But one thing is sure that you will have to ready to face the kindly suggestions πŸ– from people on the road that your headlight is on, kindly turned it off 😊

The only part of the body that has no blood supply is the cornea of the eye πŸ‘. It receives oxygen directly from the air 😱

Share with your bikers friends😎

Friday, 9 June 2017

How to detect hidden cameras in the trial rooms, and hotels?

Hidden camera lens

Shopping of clothes is popular among women. Seeing a dress, fall in love with it and trying it. But this trying can be watched by the hidden cameras in the trial rooms by the sick person's mentality. Here i am going to tell you the easy tips & tricks like detecting hidden cameras using android, using spy camera app, And other facts like two-way mirror concept that ensure you never fall into such traps.

So let's get started...

What is a two-way mirror?

A two-way mirror is a reflective mirror on one side where you can see your face and reflections but there is a transparent normal glass on the other side through which anyone can look at you directly without your knowledge. This type of mirror can be placed in the trial rooms, bathrooms and in hotels.

Two-way mirror diagram

How can we detect a two-way mirror?

1) Touch test

If you tap on the two-way mirror with your knuckle it will produce an open, hollow and reverberating sound because there is an open space in the other side contrary to a reflecting mirror which produces a dull, flat sound since it's place infront of a wall.

2) Torch test

For the proper working of two-way mirror one side of the room must be very bright while other side (observers side) must be dark
Turn off the rooms light then turn on camera flash. Now flash of camera will pass threw mirror
And you can see the observer behind the mirror in the dark room.

3) Finger test

Touch the mirror if it's two-way mirror then there is no gap between the finger and reflection. If it's ordinary or simple mirror then there will be a gap between your finger and reflection.

Two-way mirror detecting

How can we detect hidden cameras using android?

1) The easiest way to detect is using your phone calling. By dialling any number if find any disturbance, noise, low signal, call not connect issue means there is a hidden cam.

To check, do the same at your home, use your mobile close to PC or laptop, you will understand the sort of disturbance it produce.
Not all phones will do this, you have to check whether your phone buzzes or not.

2) Turn off all the lights in the room. Close all the curtains. Turn on the mobile camera. Walk around in the room. If red or purple dots shown on phones  screen then there is chance of spy camera.

To confirm it just see your TV remote through it. It will show a purple spot.
Focus on the front remote and click any Button to see the purple dot.

How to detect hidden cameras using spy camera apps?

1) Android users can try a free app-Glint finder

2) The hidden camera detector app for iPhone costs $4.99 and can be purchased in the apps store.

Both these apps require you to be fairly close to the hidden camera. The angle of hidden camera​lens and smartphone has to be the same.

A dim lit room gave us the best detection result. After turning off the light we can check for strange LED lights that shouldn't be there. Check hidden camera in conspicuous items such as eyeglasses, lamps, buttons, books, desk plant, house plant, tissues boxes, stuffed teddy bears etc. Watch for cameras near valuable items. Look for mirrors that had no meaning to be place there. Most hidden camera requires AC power to run so check for all unrecognised power plugings to the sockets.

Vivo, oppo and one plus are all owned by the same company πŸ€”

Share with your family and friends to create the awareness 😊

Can bank account hacked by hackers if he knows account number,IFSC code,PAN number and account holder name?

I know how hard it is to earn money.You earn and money save it to the bank for future purposes but in addition you have to take care of yo...