A circuit has two branches in parallel and each branch has only one element. The applied voltage and source current are v = 200 sin (200t + 30°) and i = 50 sin (200t + 50°). If one branch has capacitor, the other branch contains ?->(Show Answer!)

1. A circuit has two branches in parallel and each branch has only one element. The applied voltage and source current are v = 200 sin (200t + 30°) and i = 50 sin (200t + 50°). If one branch has capacitor, the other branch contains

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MCQ->A circuit has two branches in parallel and each branch has only one element. The applied voltage and source current are v = 200 sin (200t + 30°) and i = 50 sin (200t + 50°). If one branch has capacitor, the other branch contains....

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-> Read the following passage carefully and answer the questions given below it. Certain words/phrases have been printed in bold tohelp you locate them while answering some of the questions. During the last few years, a lot of hype has been heaped on the BRICS (Brazil, Russia, India, China, and South Africa). With their large populations and rapid growth, these countries, so the argument goes, will soon become some of the largest economies in the world and, in the case of China, the largest of all by as early as 2020. But the BRICS, as well as many other emerging-market economieshave recently experienced a sharp economic slowdown. So, is the honeymoon over? Brazil’s GDP grew by only 1% last year, and may not grow by more than 2% this year, with its potential growth barely above 3%. Russia’s economy may grow by barely 2% this year, with potential growth also at around 3%, despite oil prices being around $100 a barrel. India had a couple of years of strong growth recently (11.2% in 2010 and 7.7% in 2011) but slowed to 4% in 2012. China’s economy grew by 10% a year for the last three decades, but slowed to 7.8% last year and risks a hard landing. And South Africa grew by only 2.5% last year and may not grow faster than 2% this year. Many other previously fast-growing emerging-market economies – for example, Turkey, Argentina, Poland, Hungary, and many in Central and Eastern Europe are experiencing a similar slowdown. So, what is ailing the BRICS and other emerging markets? First, most emerging-market economies were overheating in 2010-2011, with growth above potential and inflation rising and exceeding targets. Many of them thus tightened monetary policy in 2011, with consequences for growth in 2012 that have carried over into this year. Second, the idea that emerging-market economies could fully decouple from economic weakness in advanced economies was farfetched : recession in the eurozone, near-recession in the United Kingdom and Japan in 2011-2012, and slow economic growth in the United States were always likely to affect emerging market performance negatively – via trade, financial links, and investor confidence. For example, the ongoing euro zone downturn has hurt Turkey and emergingmarket economies in Central and Eastern Europe, owing to trade links. Third, most BRICS and a few other emerging markets have moved toward a variant of state capitalism. This implies a slowdown in reforms that increase the private sector’s productivity and economic share, together with a greater economic role for state-owned enterprises (and for state-owned banks in the allocation of credit and savings), as well as resource nationalism, trade protectionism, import substitution industrialization policies, and imposition of capital controls. This approach may have worked at earlier stages of development and when the global financial crisis caused private spending to fall; but it is now distorting economic activity and depressing potential growth. Indeed, China’s slowdown reflects an economic model that is, as former Premier Wen Jiabao put it, “unstable, unbalanced, uncoordinated, and unsustainable,” and that now is adversely affecting growth in emerging Asia and in commodity-exporting emerging markets from Asia to Latin America and Africa. The risk that China will experience a hard landing in the next two years may further hurt many emerging economies. Fourth, the commodity super-cycle that helped Brazil, Russia, South Africa, and many other commodity-exporting emerging markets may be over. Indeed, a boom would be difficult to sustain, given China’s slowdown, higher investment in energysaving technologies, less emphasis on capital-and resource-oriented growth models around the world, and the delayed increase in supply that high prices induced. The fifth, and most recent, factor is the US Federal Reserve’s signals that it might end its policy of quantitative easing earlier than expected, and its hints of an even tual exit from zero interest rates. both of which have caused turbulence in emerging economies’ financial markets. Even before the Fed’s signals, emergingmarket equities and commodities had underperformed this year, owing to China’s slowdown. Since then, emerging-market currencies and fixed-income securities (government and corporate bonds) have taken a hit. The era of cheap or zerointerest money that led to a wall of liquidity chasing high yields and assets equities, bonds, currencies, and commodities – in emerging markets is drawing to a close. Finally, while many emerging-market economies tend to run current-account surpluses, a growing number of them – including Turkey, South Africa, Brazil, and India – are running deficits. And these deficits are now being financed in riskier ways: more debt than equity; more short-term debt than longterm debt; more foreign-currency debt than local-currency debt; and more financing from fickle cross-border interbank flows. These countries share other weaknesses as well: excessive fiscal deficits, abovetarget inflation, and stability risk (reflected not only in the recent political turmoil in Brazil and Turkey, but also in South Africa’s labour strife and India’s political and electoral uncertainties). The need to finance the external deficit and to avoid excessive depreciation (and even higher inflation) calls for raising policy rates or keeping them on hold at high levels. But monetary tightening would weaken already-slow growth. Thus, emerging economies with large twin deficits and other macroeconomic fragilities may experience further downward pressure on their financial markets and growth rates. These factors explain why growth in most BRICS and many other emerging markets has slowed sharply. Some factors are cyclical, but others – state capitalism, the risk of a hard landing in China, the end of the commodity supercycle -are more structural. Thus, many emerging markets’ growth rates in the next decade may be lower than in the last – as may the outsize returns that investors realised from these economies’ financial assets (currencies, equities. bonds, and commodities). Of course, some of the better-managed emerging-market economies will continue to experitnce rapid growth and asset outperformance. But many of the BRICS, along with some other emerging economies, may hit a thick wall, with growth and financial markets taking a serious beating.Which of the following statement(s) is/are true as per the given information in the passage ? A. Brazil’s GDP grew by only 1% last year, and is expected to grow by approximately 2% this year. B. China’s economy grew by 10% a year for the last three decades but slowed to 7.8% last year. C. BRICS is a group of nations — Barzil, Russia, India China and South Africa.....