For full-wave rectification, a four-diode bridge rectifier is claimed to have the following advantages over a two-diode circuit:(1) Less expensive transformer (2) Smaller size transformer and (3) Suitability for higher voltage application Of these ?->(Show Answer!)

1. For full-wave rectification, a four-diode bridge rectifier is claimed to have the following advantages over a two-diode circuit:(1) Less expensive transformer (2) Smaller size transformer and (3) Suitability for higher voltage application Of these

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MCQ->For full-wave rectification, a four-diode bridge rectifier is claimed to have the following advantages over a two-diode circuit:(1) Less expensive transformer (2) Smaller size transformer and (3) Suitability for higher voltage application Of these....

MCQ-> India is rushing headlong toward economic success and modernisation, counting on high- tech industries such as information technology and biotechnology to propel the nation toprosperity. India’s recent announcement that it would no longer produce unlicensed inexpensive generic pharmaceuticals bowed to the realities of the World TradeOrganisation while at the same time challenging the domestic drug industry to compete with the multinational firms. Unfortunately, its weak higher education sector constitutes the Achilles’ Heel of this strategy. Its systematic disinvestment in higher education inrecent years has yielded neither world-class research nor very many highly trained scholars, scientists, or managers to sustain high-tech development. India’s main competitors especially China but also Singapore, Taiwan, and South Korea — are investing in large and differentiated higher education systems. They are providingaccess to large number of students at the bottom of the academic system while at the same time building some research-based universities that are able to compete with theworld’s best institutions. The recent London Times Higher Education Supplement ranking of the world’s top 200 universities included three in China, three in Hong Kong,three in South Korea, one in Taiwan, and one in India (an Indian Institute of Technology at number 41.— the specific campus was not specified). These countries are positioningthemselves for leadership in the knowledge-based economies of the coming era. There was a time when countries could achieve economic success with cheap labour andlow-tech manufacturing. Low wages still help, but contemporary large-scale development requires a sophisticated and at least partly knowledge-based economy.India has chosen that path, but will find a major stumbling block in its university system. India has significant advantages in the 21st century knowledge race. It has a large high ereducation sector — the third largest in the world in student numbers, after China andthe United States. It uses English as a primary language of higher education and research. It has a long academic tradition. Academic freedom is respected. There are asmall number of high quality institutions, departments, and centres that can form the basis of quality sector in higher education. The fact that the States, rather than the Central Government, exercise major responsibility for higher education creates a rather cumbersome structure, but the system allows for a variety of policies and approaches. Yet the weaknesses far outweigh the strengths. India educates approximately 10 per cent of its young people in higher education compared with more than half in the major industrialised countries and 15 per cent in China. Almost all of the world’s academic systems resemble a pyramid, with a small high quality tier at the top and a massive sector at the bottom. India has a tiny top tier. None of its universities occupies a solid position at the top. A few of the best universities have some excellent departments and centres, and there is a small number of outstanding undergraduate colleges. The University Grants Commission’s recent major support of five universities to build on their recognised strength is a step toward recognising a differentiated academic system and fostering excellence. At present, the world-class institutions are mainly limited to the Indian Institutes of Technology (IITs), the Indian Institutes of Management (IIMs) and perhaps a few others such as the All India Institute of Medical Sciences and the Tata Institute of Fundamental Research. These institutions, combined, enroll well under 1 percent of the student population. India’s colleges and universities, with just a few exceptions, have become large, under-funded, ungovernable institutions. At many of them, politics has intruded into campus life, influencing academic appointments and decisions across levels. Under-investment in libraries, information technology, laboratories, and classrooms makes it very difficult to provide top-quality instruction or engage in cutting-edge research.The rise in the number of part-time teachers and the freeze on new full-time appointments in many places have affected morale in the academic profession. The lackof accountability means that teaching and research performance is seldom measured. The system provides few incentives to perform. Bureaucratic inertia hampers change.Student unrest and occasional faculty agitation disrupt operations. Nevertheless, with a semblance of normality, faculty administrators are. able to provide teaching, coordinate examinations, and award degrees. Even the small top tier of higher education faces serious problems. Many IIT graduates,well trained in technology, have chosen not to contribute their skills to the burgeoning technology sector in India. Perhaps half leave the country immediately upon graduation to pursue advanced study abroad — and most do not return. A stunning 86 per cent of students in science and technology fields from India who obtain degrees in the United States do not return home immediately following their study. Another significant group, of about 30 per cent, decides to earn MBAs in India because local salaries are higher.—and are lost to science and technology.A corps of dedicated and able teachers work at the IlTs and IIMs, but the lure of jobs abroad and in the private sector make it increasingly difficult to lure the best and brightest to the academic profession.Few in India are thinking creatively about higher education. There is no field of higher education research. Those in government as well as academic leaders seem content to do the “same old thing.” Academic institutions and systems have become large and complex. They need good data, careful analysis, and creative ideas. In China, more than two-dozen higher education research centers, and several government agencies are involved in higher education policy.India has survived with an increasingly mediocre higher education system for decades.Now as India strives to compete in a globalized economy in areas that require highly trained professionals, the quality of higher education becomes increasingly important.India cannot build internationally recognized research-oriented universities overnight,but the country has the key elements in place to begin and sustain the process. India will need to create a dozen or more universities that can compete internationally to fully participate in the new world economy. Without these universities, India is destined to remain a scientific backwater.Which of the following ‘statement(s) is/are correct in the context of the given passage ? I. India has the third largest higher education sector in the world in student numbers. II. India is moving rapidly toward economic success and modernisation through high tech industries such as information technology and bitechonology to make the nation to prosperity. III. India’s systematic disinvestment in higher education in recent years has yielded world class research and many world class trained scholars, scientists to sustain high-tech development.....

MCQ-> In a modern computer, electronic and magnetic storage technologies play complementary roles. Electronic memory chips are fast but volatile (their contents are lost when the computer is unplugged). Magnetic tapes and hard disks are slower, but have the advantage that they are non-volatile, so that they can be used to store software and documents even when the power is off.In laboratories around the world, however, researchers are hoping to achieve the best of both worlds. They are trying to build magnetic memory chips that could be used in place of today’s electronics. These magnetic memories would be nonvolatile; but they would also he faster, would consume less power, and would be able to stand up to hazardous environments more easily. Such chips would have obvious applications in storage cards for digital cameras and music- players; they would enable handheld and laptop computers to boot up more quickly and to operate for longer; they would allow desktop computers to run faster; they would doubtless have military and space-faring advantages too. But although the theory behind them looks solid, there are tricky practical problems and need to be overcome.Two different approaches, based on different magnetic phenomena, are being pursued. The first, being investigated by Gary Prinz and his colleagues at the Naval Research Laboratory (NRL) in Washington, D.c), exploits the fact that the electrical resistance of some materials changes in the presence of magnetic field— a phenomenon known as magneto- resistance. For some multi-layered materials this effect is particularly powerful and is, accordingly, called “giant” magneto-resistance (GMR). Since 1997, the exploitation of GMR has made cheap multi-gigabyte hard disks commonplace. The magnetic orientations of the magnetised spots on the surface of a spinning disk are detected by measuring the changes they induce in the resistance of a tiny sensor. This technique is so sensitive that it means the spots can be made smaller and packed closer together than was previously possible, thus increasing the capacity and reducing the size and cost of a disk drive. Dr. Prinz and his colleagues are now exploiting the same phenomenon on the surface of memory chips, rather spinning disks. In a conventional memory chip, each binary digit (bit) of data is represented using a capacitor-reservoir of electrical charge that is either empty or fill -to represent a zero or a one. In the NRL’s magnetic design, by contrast, each bit is stored in a magnetic element in the form of a vertical pillar of magnetisable material. A matrix of wires passing above and below the elements allows each to be magnetised, either clockwise or anti-clockwise, to represent zero or one. Another set of wires allows current to pass through any particular element. By measuring an element’s resistance you can determine its magnetic orientation, and hence whether it is storing a zero or a one. Since the elements retain their magnetic orientation even when the power is off, the result is non-volatile memory. Unlike the elements of an electronic memory, a magnetic memory’s elements are not easily disrupted by radiation. And compared with electronic memories, whose capacitors need constant topping up, magnetic memories are simpler and consume less power. The NRL researchers plan to commercialise their device through a company called Non-V olatile Electronics, which recently began work on the necessary processing and fabrication techniques. But it will be some years before the first chips roll off the production line.Most attention in the field in focused on an alternative approach based on magnetic tunnel-junctions (MTJs), which are being investigated by researchers at chipmakers such as IBM, Motorola, Siemens and Hewlett-Packard. IBM’s research team, led by Stuart Parkin, has already created a 500-element working prototype that operates at 20 times the speed of conventional memory chips and consumes 1% of the power. Each element consists of a sandwich of two layers of magnetisable material separated by a barrier of aluminium oxide just four or five atoms thick. The polarisation of lower magnetisable layer is fixed in one direction, but that of the upper layer can be set (again, by passing a current through a matrix of control wires) either to the left or to the right, to store a zero or a one. The polarisations of the two layers are then either the same or opposite directions.Although the aluminum-oxide barrier is an electrical insulator, it is so thin that electrons are able to jump across it via a quantum-mechanical effect called tunnelling. It turns out that such tunnelling is easier when the two magnetic layers are polarised in the same direction than when they are polarised in opposite directions. So, by measuring the current that flows through the sandwich, it is possible to determine the alignment of the topmost layer, and hence whether it is storing a zero or a one.To build a full-scale memory chip based on MTJs is, however, no easy matter. According to Paulo Freitas, an expert on chip manufacturing at the Technical University of Lisbon, magnetic memory elements will have to become far smaller and more reliable than current prototypes if they are to compete with electronic memory. At the same time, they will have to be sensitive enough to respond when the appropriate wires in the control matrix are switched on, but not so sensitive that they respond when a neighbouring elements is changed. Despite these difficulties, the general consensus is that MTJs are the more promising ideas. Dr. Parkin says his group evaluated the GMR approach and decided not to pursue it, despite the fact that IBM pioneered GMR in hard disks. Dr. Prinz, however, contends that his plan will eventually offer higher storage densities and lower production costs.Not content with shaking up the multi-billion-dollar market for computer memory, some researchers have even more ambitious plans for magnetic computing. In a paper published last month in Science, Russell Cowburn and Mark Well and of Cambridge University outlined research that could form the basis of a magnetic microprocessor — a chip capable of manipulating (rather than merely storing) information magnetically. In place of conducting wires, a magnetic processor would have rows of magnetic dots, each of which could be polarised in one of two directions. Individual bits of information would travel down the rows as magnetic pulses, changing the orientation of the dots as they went. Dr. Cowbum and Dr. Welland have demonstrated how a logic gate (the basic element of a microprocessor) could work in such a scheme. In their experiment, they fed a signal in at one end of the chain of dots and used a second signal to control whether it propagated along the chain.It is, admittedly, a long way from a single logic gate to a full microprocessor, but this was true also when the transistor was first invented. Dr. Cowburn, who is now searching for backers to help commercialise the technology, says he believes it will be at least ten years before the first magnetic microprocessor is constructed. But other researchers in the field agree that such a chip, is the next logical step. Dr. Prinz says that once magnetic memory is sorted out “the target is to go after the logic circuits.” Whether all-magnetic computers will ever be able to compete with other contenders that are jostling to knock electronics off its perch — such as optical, biological and quantum computing — remains to be seen. Dr. Cowburn suggests that the future lies with hybrid machines that use different technologies. But computing with magnetism evidently has an attraction all its own.In developing magnetic memory chips to replace the electronic ones, two alternative research paths are being pursued. These are approaches based on:
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MCQ->For full wave rectification four diode bridge rectifier is claimed to have following advantages: Less expensive transformerSmall size transformerSuitable for higher voltage applications Which of these are correct?....

MCQ-> Read the passage given below and answer the questions that follow:-Brazil is a top exporter of every commodity that has seen dizzying price surges - iron ore, soybeans, sugar - producing a golden age for economic growth Foreign money-flows into Brazilian stocks and bonds climbed heavenward, up more than tenfold, from $5 billion a year in early 2007 to more than $50 billion in the twelve months through March 2011.The flood of foreign money buying up Brazilian assets has made the currency one of the most expensive in the world, and Brazil one of the most costly, overhyped economies. Almost every major emerging- market currency has strengthened against the dollar over the last decade, but the Brazilian Real is on a path alone, way above the pack, having doubled in value against the dollar.Economists have all kinds of fancy ways to measure the real value of a currency, but when a country is pricing itself this far out of the competition, you can feel it on the ground. In early 2011 the major Rio paper, 0 Globo, ran a story on prices showing that croissants are more expensive than they are in Paris, haircuts cost more than they do in London, bike rentals are more expensive than in Amsterdam, and movie tickets sell for higher prices than in Madrid. A rule of the road: if the local prices in an emerging market country feel expensive even to a visitor from a rich nation, that country is probably not a breakout nation.There is no better example of how absurd it is to lump all the big emerging markets together than the frequent pairing of Brazil and China. Those who make this comparison are referring only to the fact that they are the biggest players in their home regions, not to the way the economies actually run. Brazil is the world‘s leading exporter of many raw materials, and China is the leading importer; that makes them major trade partners - China surpassed the United States as Brazil's leading trade partner in 2009 f but it also makes them opposites in almost every important economic respect: Brazil is the un-China, with interest rates that are too high, and a currency that is too expensive. It spends too little on roads and too much on welfare, and as a result has a very un-China-like growth record.It may not be entirely fair to compare economic growth in Brazil with that of its Asian counterparts, because Brazil has a per capita income of $12,000, more than two times China's and nearly ten times India's. But even taking into account the fact that it is harder for rich nations to grow quickly, Brazil's growth has been disappointing. Since the early 19805 the Brazilian growth rate has oscillated around an average of 2.5 percent, spiking only in concert with increased prices for Brazil's key commodity exports. While China has been criticized for pursuing "growth at any cost," Brazil has sought to secure "stability at any cost." Brazil's caution stems from its history of financial crises, in which overspending produced debt, humiliating defaults, and embarrassing devaluations, culminating in a disaster that is still recent enough to be fresh in every Brazilian adult's memory: the hyperinflation that started in the early 19805 and peaked in 1994, at the vertiginous annual rate of 2,100 percent.Wages were pegged to inflation but were increased at varying intervals in different industries, 50 workers never really knew whether they were making good money or not. As soon as they were paid, they literally ran to the store with cash to buy food, and they could afford little else, causing non-essential industries to start to die. Hyperinflation finally came under control in l995, but it left a problem of regular behind. Brazil has battled inflation ever since by maintaining one of the highest interest rates in the emerging world. Those high rates have attracted a surge of foreign money, which is partly why the Brazilian Real is so expensive relative to comparable currencies.There is a growing recognition that China faces serious "imbalances" that could derail its long economic boom. Obsessed until recently with high growth, China has been pushing too hard to keep its currency too cheap (to help its export industries compete), encouraging excessively high savings and keeping interest rates rock bottom to fund heavy spending on roads and ports. China is only now beginning to consider a shift in spending priorities to create social programs that protect its people from the vicissitudes of old age and unemployment.Brazil’s economy is just as badly out of balance, though in opposite ways. While China has introduced reforms relentlessly for three decades, opening itself up to the world even at the risk of domestic instability, Brazil has pushed reforms only in the most dire circumstances, for example, privatizing state companies when the government budget is near collapse. Fearful of foreign shocks, Brazil is still one of the most closed economies in the emerging world - total imports and exports account for only 15 percent of GDP - despite its status as the world's leading exporter of sugar, orange juice, coffee, poultry, and beef.To pay for its big government, Brazil has jacked up taxes and now has a tax burden that equals 38 percent of GDP, the highest in the emerging world, and very similar to the tax burden in developed European welfare states, such as Norway and France. This heavy load of personal and corporate tax on a relatively poor country means that businesses don’t have the money to invest in new technology or training, which in turn means that industry is not getting more efficient. Between 1986 and 2008 Brazil’s productivity grew at an annual rate of :about 0.2 percent, compared to 4 percent in China. Over the same period, productivity grew in India at close to 3 percent and in South Korea and Thailand at close to 2 percent. According to the passage, the major concern facing the Brazil economy is:
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