The ability to heat metal most rapidly in: ?->(Show Answer!)

1. The ability to heat metal most rapidly in:

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MCQ->The simplest method of welding two pieces of metal together is known as pressure welding.The ends of a metal are heated to a white heat-for iron,the welding temperature should be about 1300C-in a flame.At this temperature the metal becomes plastic.The ends are pressed or hammered together,and the joint is smoothed off.Care must be taken to ensure that surfaces are thoroughly clean first,for dirt will weaken the weld.Moreover,the heating of iron or steel to a high temperature cause oxidation,and a film of oxide is added to the heated surfaces.For this reason,flux is applied to the heated metal.At welding heat,flux melts and the oxide particles are dissolved in it together with any other impurities which may be present.The metal surfaces are pressed together,and the flux is squeezed out from the center of the weld.A number of different types of weld may be used,but for fairly thick bars of metals,a vee-shaped belt should be normally employed.It is rather stronger than ordinary butt weld. The simplest way of welding two pieces of metal together is....

MCQ-> The broad scientific understanding today is that our planet is experiencing a warming trend over and above natural and normal variations that is almost certainly due to human activities associated with large-scale manufacturing. The process began in the late 1700s with the Industrial Revolution, when manual labor, horsepower, and water power began to be replaced by or enhanced by machines. This revolution, over time, shifted Britain, Europe, and eventually North America from largely agricultural and trading societies to manufacturing ones, relying on machinery and engines rather than tools and animals.The Industrial Revolution was at heart a revolution in the use of energy and power. Its beginning is usually dated to the advent of the steam engine, which was based on the conversion of chemical energy in wood or coal to thermal energy and then to mechanical work primarily the powering of industrial machinery and steam locomotives. Coal eventually supplanted wood because, pound for pound, coal contains twice as much energy as wood (measured in BTUs, or British thermal units, per pound) and because its use helped to save what was left of the world's temperate forests. Coal was used to produce heat that went directly into industrial processes, including metallurgy, and to warm buildings, as well as to power steam engines. When crude oil came along in the mid- 1800s, still a couple of decades before electricity, it was burned, in the form of kerosene, in lamps to make light replacing whale oil. It was also used to provide heat for buildings and in manufacturing processes, and as a fuel for engines used in industry and propulsion.In short, one can say that the main forms in which humans need and use energy are for light, heat, mechanical work and motive power, and electricity which can be used to provide any of the other three, as well as to do things that none of those three can do, such as electronic communications and information processing. Since the Industrial Revolution, all these energy functions have been powered primarily, but not exclusively, by fossil fuels that emit carbon dioxide (CO2), To put it another way, the Industrial Revolution gave a whole new prominence to what Rochelle Lefkowitz, president of Pro-Media Communications and an energy buff, calls "fuels from hell" - coal, oil, and natural gas. All these fuels from hell come from underground, are exhaustible, and emit CO2 and other pollutants when they are burned for transportation, heating, and industrial use. These fuels are in contrast to what Lefkowitz calls "fuels from heaven" -wind, hydroelectric, tidal, biomass, and solar power. These all come from above ground, are endlessly renewable, and produce no harmful emissions.Meanwhile, industrialization promoted urbanization, and urbanization eventually gave birth to suburbanization. This trend, which was repeated across America, nurtured the development of the American car culture, the building of a national highway system, and a mushrooming of suburbs around American cities, which rewove the fabric of American life. Many other developed and developing countries followed the American model, with all its upsides and downsides. The result is that today we have suburbs and ribbons of highways that run in, out, and around not only America s major cities, but China's, India's, and South America's as well. And as these urban areas attract more people, the sprawl extends in every direction.All the coal, oil, and natural gas inputs for this new economic model seemed relatively cheap, relatively inexhaustible, and relatively harmless-or at least relatively easy to clean up afterward. So there wasn't much to stop the juggernaut of more people and more development and more concrete and more buildings and more cars and more coal, oil, and gas needed to build and power them. Summing it all up, Andy Karsner, the Department of Energy's assistant secretary for energy efficiency and renewable energy, once said to me: "We built a really inefficient environment with the greatest efficiency ever known to man."Beginning in the second half of the twentieth century, a scientific understanding began to emerge that an excessive accumulation of largely invisible pollutants-called greenhouse gases - was affecting the climate. The buildup of these greenhouse gases had been under way since the start of the Industrial Revolution in a place we could not see and in a form we could not touch or smell. These greenhouse gases, primarily carbon dioxide emitted from human industrial, residential, and transportation sources, were not piling up along roadsides or in rivers, in cans or empty bottles, but, rather, above our heads, in the earth's atmosphere. If the earth's atmosphere was like a blanket that helped to regulate the planet's temperature, the CO2 buildup was having the effect of thickening that blanket and making the globe warmer.Those bags of CO2 from our cars float up and stay in the atmosphere, along with bags of CO2 from power plants burning coal, oil, and gas, and bags of CO2 released from the burning and clearing of forests, which releases all the carbon stored in trees, plants, and soil. In fact, many people don't realize that deforestation in places like Indonesia and Brazil is responsible for more CO2 than all the world's cars, trucks, planes, ships, and trains combined - that is, about 20 percent of all global emissions. And when we're not tossing bags of carbon dioxide into the atmosphere, we're throwing up other greenhouse gases, like methane (CH4) released from rice farming, petroleum drilling, coal mining, animal defecation, solid waste landfill sites, and yes, even from cattle belching. Cattle belching? That's right-the striking thing about greenhouse gases is the diversity of sources that emit them. A herd of cattle belching can be worse than a highway full of Hummers. Livestock gas is very high in methane, which, like CO2, is colorless and odorless. And like CO2, methane is one of those greenhouse gases that, once released into the atmosphere, also absorb heat radiating from the earth's surface. "Molecule for molecule, methane's heat-trapping power in the atmosphere is twenty-one times stronger than carbon dioxide, the most abundant greenhouse gas.." reported Science World (January 21, 2002). “With 1.3 billion cows belching almost constantly around the world (100 million in the United States alone), it's no surprise that methane released by livestock is one of the chief global sources of the gas, according to the U.S. Environmental Protection Agency ... 'It's part of their normal digestion process,' says Tom Wirth of the EPA. 'When they chew their cud, they regurgitate [spit up] some food to rechew it, and all this gas comes out.' The average cow expels 600 liters of methane a day, climate researchers report." What is the precise scientific relationship between these expanded greenhouse gas emissions and global warming? Experts at the Pew Center on Climate Change offer a handy summary in their report "Climate Change 101. " Global average temperatures, notes the Pew study, "have experienced natural shifts throughout human history. For example; the climate of the Northern Hemisphere varied from a relatively warm period between the eleventh and fifteenth centuries to a period of cooler temperatures between the seventeenth century and the middle of the nineteenth century. However, scientists studying the rapid rise in global temperatures during the late twentieth century say that natural variability cannot account for what is happening now." The new factor is the human factor-our vastly increased emissions of carbon dioxide and other greenhouse gases from the burning of fossil fuels such as coal and oil as well as from deforestation, large-scale cattle-grazing, agriculture, and industrialization.“Scientists refer to what has been happening in the earth’s atmosphere over the past century as the ‘enhanced greenhouse effect’”, notes the Pew study. By pumping man- made greenhouse gases into the atmosphere, humans are altering the process by which naturally occurring greenhouse gases, because of their unique molecular structure, trap the sun’s heat near the earth’s surface before that heat radiates back into space."The greenhouse effect keeps the earth warm and habitable; without it, the earth's surface would be about 60 degrees Fahrenheit colder on average. Since the average temperature of the earth is about 45 degrees Fahrenheit, the natural greenhouse effect is clearly a good thing. But the enhanced greenhouse effect means even more of the sun's heat is trapped, causing global temperatures to rise. Among the many scientific studies providing clear evidence that an enhanced greenhouse effect is under way was a 2005 report from NASA's Goddard Institute for Space Studies. Using satellites, data from buoys, and computer models to study the earth's oceans, scientists concluded that more energy is being absorbed from the sun than is emitted back to space, throwing the earth's energy out of balance and warming the globe."Which of the following statements is correct? (I) Greenhouse gases are responsible for global warming. They should be eliminated to save the planet (II) CO2 is the most dangerous of the greenhouse gases. Reduction in the release of CO2 would surely bring down the temperature (III) The greenhouse effect could be traced back to the industrial revolution. But the current development and the patterns of life have enhanced their emissions (IV) Deforestation has been one of the biggest factors contributing to the emission of greenhouse gases Choose the correct option:....

MCQ->Choose the set in which the statements are most logically related. A. All men are men of scientific ability. B. Some women are women of scientific ability. C. Some men are men of artistic genius. D. Some men and women are of scientific ability. E. All men of artistic genius are men of scientific ability. F. Some women of artistic genius are women of scientific ability.....

MCQ-> Read the following passage carefully and answer these question. Certain words/phrase have been printed in bold to help you locate them while answering some of the question.Over the last three centuries, the world economy has evolved from a predominantly agriculture-based system to a digital economic system. The earlier economies were mainly agrarian. In this era, capital did play a role, as did technological innovations such as the plough, the steamboat or the train. But land and labour were more critical.With the industrial revolution, the global economy was primarily driven by the ability to produce goods for the mass market. This led to the industrial economy where capital and labour were the most important drivers. In the service economy, the wealth created by services exceeded the wealth created through manufacturing. Here, the ability of the service provider to establish a sound business gave him access to additional capital. This evolved into a global economy where goods and services were traded across international borders, with little restriction. ln this period, capital started flowing across border on all large scale for the first time.The last five years have seen the advent of the digital economy where technology is becoming the driving force. With information being the driver of value and wealth creation, information logy is becoming the key to success in a growing number of industries. In the digital economy, the power of innovation and ideas gained the upper hand over direct access to capital.The Indian economy is in a unique in terms of its economic evaluation. While manufacturing and service industries in India cannot freely access capital, the new breed of IT:- based industries have access to venture capital and private equity. The country's potential in this emerging sector has opened the doors to capital inflows that are still not available to traditional industries.There are two key trends which will boost the democratization of capital, either directly as funding sources or indirectly.More effective capital market routes---especially for information - based and software companies.This is already happening rapidly. A market that was supposed to be stagnating with no public offering from the manufacturing sector in the first quarter of the fiscal year may see as many see as many as 20-25 new software issues this year. Numerous internet and e-commerce companies are tapping funds through the capital market. For the financial intermediaries as well as for the investing public, dot com or 'info' initial offerings are fast becoming attractive to investment alternatives to traditional manufacturing or financial sector offers.With more effective capital markets, for high potential IT stocks, 'critical mass', which in the industrial economy' was primary in ensuring a company's ability to raise capital, will cases to matter. This underlines the manner in which a burgeoning digital economy has led to a redeployment of capital from a concentrated segment to the smaller knowledge entrepreneur.A greater number of venture capitalists actively seeking to fund budding knowledge entrepreneurs. Along with the rise in Net entrepreneurs one has seen the emergence of a new breed of venture capitalists who recognize the potential that resides in these ideas. The emergence and strengthening of the virtual economy necessitates sources of funds at the' ideation' stage where business plans may still be at the in fancy stage and potential not clearly identified.This need is being fulfilled by the incubator funds or the angle investors who hand-hold internet startups and other info tech ventures till the stage at which they can attract bigger investors. Instead of looking at high risk but big ventures, this genre of venture capitalists are looking at investments in companies which have the potential of excellent valuations in the future on the strength of their ideas.which as the following has been related as most crucial in agro-based economy ? 1.Capital steamboat and trains. 2.Technological innovations like plough,etc. 3.Labour and land.....

MCQ->The ability to heat metal most rapidly in:....