Top discounted 9 gadgets that you can buy from Amazon great Indian festival

Festival season is starting Amazon gives blockbuster deals on gadgets grab them now last chance to take your gadget at low cost. Below are top 9 discounted gadgets that you can buy. These offers valid til 23th sept. So hurry up guyzz😃

Moto G5s Plus

• 13+13MP dual back camera
• 4GB RAM 
• Dual nano SIM with dual-standby (4G+4G); Metal body with fingerprint reader
• Android v7.1.1 Nougat operating system with 2.0GHz Snapdragon 625 octa-core processor
• 3000mAH Lithium-ion battery with 15W Turbo Charging
• 1 year manufacturer warranty for device and 6 months manufacturer warranty for in-box accessories including battery from the date of purchase
• Prize: 15999
• BUY NOW

LENOVO K4 NOTE

• 13+5MP dual back camera and 13MP front facing camera with party flash
• Android v7.1.1 Nougat operating system with 2.3GHz Helio X23 10-core processor
• 13.97 (5.5-inch) Full HD (1920 x 1080) IPS touchscreen with Gorilla Glass protection
• 4GB RAM and 64GB internal memory expandable up to 128GB
• Dual nano SIM with dual-standby (4G+4G)
• 4000mAH all day battery with 15W Turbo Charging
• 1 year manufacturer warranty for device and 6 months manufacturer warranty for in-box accessories including batteries from the date of purchase
• Prize:12999
• BUY NOW

REDMI 4A

• 13MP primary camera with 5-elements lens, f/2.2 aperture, PDAF, high dynamic range (HDR), panaroma, 1080p full HD video recording and 5MP front facing camera
• 12.7 centimeters (5-inch) display with 1280 x 720 pixels resolution and 293 ppi pixel density
• Android v6.0.1 Marshmallow operating system with up to 1.4GHz Qualcomm Snapdragon 435 octa core processor with Adreno 505 GPU, 3GB RAM, 32GB internal memory expandable up to 128GB and dual SIM (micro+nano) dual-standby (4G+4G)
• 4100mAH lithium-ion battery providing talk-time of 36 hours and standby time of 432 hours
• 1 year manufacturer warranty for device and 6 months manufacturer warranty for in-box accessories including batteries from the date of purchase
• Prize:8499
• BUY NOW

MOTO G5 PLUS

• 12MP primary camera (f1.7) with dual auto focus pixels and 5MP front facing camera, color balancing dual LED flash, 8x digital zoom for photos, 4x for video, drag to focus exposure
• 4GB RAM and 32GB internal memory expandable up to 128GB
• Metal body with finger-print reader
• 13.2 centimeters (5.2-inch) Full HD TFT IPS display with 1920 x 1080 pixels resolution with Corning Gorilla Glass 3 capacitive touchscreen
• Android v7 Nougat operating system | Qualcomm Snapdragon 625 octa-core processor (2GHz) with Adreno 506 GPU
• Dual nano SIM with dual-standby (4G+4G)
• 3000mAH lithium-ion battery
• BUY NOW

MI MAX2

• 12MP primary camera with f/2.2, phase detection autofocus, dual-LED (dual tone) flash, 1/2.9" sensor size, 1.25 µm pixel size, touch focus, face detection, HDR, panorama and 5MP front facing camera
• 16.35 centimeters (6.44-inch) IPS LCD capacitive touchscreen with 1920 x 1080 pixels resolution, 342 ppi pixel density and 16M color support
• Android v7.1.1 Nougat with Miui 8 operating system with 2GHz Qualcomm Snapdragon 625 Cortex-A53 octa core processor, Adreno 506 GPU, 4GB RAM, 32GB internal memory expandable up to 128GB and dual SIM (micro+nano) dual-standby (4G+4G)
• 5300mAH lithium-polymer battery
• 1 year manufacturer warranty for device and 6 months manufacturer warranty for in-box accessories including batteries from the date of purchase
• PRize:12999
• BUY NOW

LG Q6

• 13MP primary camera and 5MP front facing camera with wide angle selfie
• 13.97 centimeters (5.5-inch) IPS in cell touch capacitive touchscreen with 1080 x 2160 pixels resolution, 442 ppi pixel density and 16M color support with Corning Gorilla Glass 3
• Android v7.1 Nougat operating system with 1.4GHz Qualcomm Snapdragon 435 octa core processor, 3GB RAM, 32GB internal memory expandable up to 2TB and dual SIM (nano+nano) dual-standby (4G+4G)
• 3000mAH lithium-ion battery providing talk-time of 14 hours and standby time of 136 hours
• 1 year manufacturer warranty for device and 6 months manufacturer warranty for in-box accessories including batteries from the date of purchase
• BUY NOW

JBL GO WIRELESS PORTABLE BLUETOOTH

• Great sound and small form factor
• Wireless bluetooth streaming
• Speakerphone and durable material
• Compatible with smartphones and tablets
• Connector Type: Bluetooth, Aux-in
• Prize 1899
• BUY NOW

MI 20000 MAH POWER BANK

• Lithium polymer battery makes it more durable and optimises charging efficiency
• Experience ultra-fast charging Quick Charge 3.0 support when charging one device or 5.1V/3.6A support when charging two devices at once
• 20000mAH Mi power bank 2 plays well with others, including devices from Mi, Apple, Samsung and more
• Prize 1799
• BUY NOW

JIOFI

• Enjoy 4G features on 2G/3G smart phones
• True 4G speed - download speed up to 150 Mbps and upload speed up to 50 Mbps
• Make video and HD voice calls, audio and video conference, send SMS with Jio 4G voice app
• Recommended to connect up to 10 Wi-Fi enabled devices (smartphone, laptops, tablets and even smart TVs)
• Prize 999
• BUY NOW

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.

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.

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

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.

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.