The unit of magneto motive force is : ?->(Show Answer!)

1. The unit of magneto motive force is :

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MCQ-> Read the following passages carefully and answer the questions given at the end of each passage.PASSAGE 3Typically women participate in the labour force at a very high rate in poor rural countries. The participation rate then falls as countries industrialise and move into the middle income class. Finally, if the country grows richer still, more families have the resources for higher education for women and from there they often enter the labour force in large numbers. Usually, economic growth goes hand in hand with emancipation of women. Among rich countries according to a 2015 study, female labour force participation ranges from nearly 80 percent in Switzerland to 70 percent in Germany and less than 60 Percent in the United States and Japan. Only 68 Percent of Canadian omen participated in the workforce in 1990; two decades later that increased to 74 Percent largely due to reforms including tax cuts for second earners and new childcare services. In Netherlands the female labour participation rate doubled since 1980 to 74 Percent as a result of expanded parental leave policies and the spread of flexible, part time working arrangements. In a 2014 survey of 143 emerging countries, the World Bank found that 90 Percent have at least one law that limits the economic opportunities available to women. These laws include bans or limitations on women owning property, opening a bank account, signing a contract, entering a courtroom, travelling alone, driving or controlling family finances. Such restrictions are particularly prevalent in the Middle East and South Asia with the world’s lowest female labour force participation, 26 and 35 percent respectively. According to date available with the International Labour Organisation (ILO), between 2004 and 2011, when the Indian economy grew at a healthy average of about 7 percent, there was a decline in female participation in the country’s labour force from over 35 percent to 25 percent. India also posted the lowest rate of female participation in the workforce among BRIC countries. India’s performance in female workforce participation stood at 27 percent, significantly behind China (64 percent), Brazil (59 percent), Russian Federation (57 percent), and South Africa (45 percent). The number of working women in India had climbed between 2000 and 2005, increasing from 34 percent to 37 percent, but since then the rate of women in the workforce has to fallen to 27 percent as of 2014, said the report citing data from the World Bank. The gap between male and female workforce participation in urban areas in 2011 stood at 40 percent, compared to rural areas where the gap was about 30 percent. However, in certain sectors like financial services, Indian women lead the charge. While only one in 10 Indian companies are led by women, more than half of them are in the financial sector. Today, women head both the top public and private banks in India. Another example is India’s aviation sector, 11.7 percent of India’s 5,100 pilots are women, versus 3 percent worldwide. But these successes only represent a small of women in the country. India does poorly in comparison to its neighbours despite a more robust economic growth. In comparison to India, women in Bangladesh have increased their participation in the labour market, which is due to the growth of the ready- made garment sector and a push to rural female employment. In 2015, women comprised of 43 percent of the labour force in Bangladesh. The rate has also increased in Pakistan, albeit from a very low starting point, while participation has remained relatively stable in Sri Lanka. Myanmar with 79 percent and Malaysia with 49 percent are also way ahead of India. Lack of access to higher education, fewer job opportunities, the lack of flexibility in working conditions, as well as domestic duties are cited as factors behind the low rates. Marriage significantly reduced the probability of women working by about 8 percent in rural areas and more than twice as much in urban areas, said an Assocham report. ILO attributes this to three factors: increasing educational enrolment, improvement in earning of male workers that discourage women’s economic participation, and lack of employment opportunities at certain levels of skills and qualifications discouraging women to seek work. The hurdles to working women often involve a combination of written laws and cultural norms. Cultures don’t change overnight but laws can. The IMF says that even a small step such as countries granting women the right to open a bank account can lead to substantial increase in female labour force participation over the next seven years. According to the United Nations Economic and Social Commission for Asia and the Pacific (ESCAP), even a 10 percent increase in women participating in the workforce can boost gross domestic product (GDP) by 0.3 percent. The OECD recently estimated that eliminating the gender gap would lead to an overall increase in GDP of 12 percent in its member nations between 2015 and 2030. The GDP gains would peak close to 20 percent in both Japan and South Korea and more than 20 percent in Italy. A similar analysis by Booz and Company showed that closing gender gap in emerging countries could yield even larger gains in GDP by 2020, ranging from a 34 percent gain in Egypt to 27 percent in India and 9 percent in Brazil. According to the above passage, though there are many reasons for low female labour force participation, the most important focus of the passage is on
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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->Pick out thể one word for - a secret arrangement....