Assertion (A): When an electron is revolving in its orbit and magnetic field is also present, the angular frequency of electron will be affected by the magnetic field.Reason (R): In the case of electron revolving in its orbit in the presence of magne ?->(Show Answer!)

1. Assertion (A): When an electron is revolving in its orbit and magnetic field is also present, the angular frequency of electron will be affected by the magnetic field.Reason (R): In the case of electron revolving in its orbit in the presence of magnetic field, the orbital magnetic dipole moment is not affected by the presence of magnetic field.

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MCQ->Assertion (A): When an electron is revolving in its orbit and magnetic field is also present, the angular frequency of electron will be affected by the magnetic field.Reason (R): In the case of electron revolving in its orbit in the presence of magnetic field, the orbital magnetic dipole moment is not affected by the presence of magnetic field.

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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->Assertion (A): If an electron having charge e is revolving in an orbit of radius R and with angular velocity ω, the magnetic dipole moment of orbit is 0.5 eωR2.Reason (R): Orbital angular momentum and magnetic dipole moment are always equal.

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MCQ-> Read the following passage carefully and answer the questions given at the end. When Ratan Tata moved the Supreme Court, claiming his right to privacy had been violated, he called Harish Salve. The choice was not surprising. The former solicitor general had been topping the legal charts ever since he scripted a surprising win for Mukesh Ambani against his brother Anil. That dispute set the gold standard for legal fees. On Mukesh’s side were Salve, Rohinton Nariman, and Abhishek Manu Singhvi. The younger brother had an equally formidable line-up led by Ram Jethmalani and Mukul Rohatgi.The dispute dated back three-and-a-half years to when Anil filed case against his brother for reneging on an agreement to supply 28 million cubic metres of gas per day from its Krishna-Godavari basin fields at a rate of $ 2.34 for 17 years. The average legal fee was Rs. 25 lakh for a full day's appearance, not to mention the overnight stays at Mumbai's five-star suites, business class travel, and on occasion, use of the private jet. Little wonder though that Salve agreed to take on Tata’s case pro bono. He could afford philanthropy with one of India’s wealthiest tycoons.The lawyers’ fees alone, at a conservative estimate, must have cost the Ambanis at least Rs. 15 crore each. Both the brothers had booked their legal teams in the same hotel, first the Oberoi and, after the 26/ ll Mumbai attacks, the Trident. lt’s not the essentials as much as the frills that raise eyebrows. The veteran Jethmalani is surprisingly the most modest in his fees since he does not charge rates according to the strength of the client's purse. But as the crises have multiplied, lawyers‘fees have exploded.The 50 court hearings in the Haldia Petrochemicals vs. the West Bengal Government cost the former a total of Rs. 25 crore in lawyer fees and the 20 hearings in the Bombay Mill Case, which dragged on for three years, cost the mill owners almost Rs. 10 crore. Large corporate firms, which engage star counsels on behalf of the client, also need to know their quirks. For instance, Salve will only accept the first brief. He will never be the second counsel in a case. Some lawyers prefer to be paid partly in cash but the best are content with cheques. Some expect the client not to blink while picking up a dinner tab of Rs. 1.75 lakh at a Chennai five star. A lawyer is known to carry his home linen and curtains with him while travelling on work. A firm may even have to pick up a hot Vertu phone of the moment or a Jaeger-LeCoutre watch of the hour to keep a lawyer in good humour.Some are even paid to not appear at all for the other side - Aryama Sundaram was retained by Anil Ambani in the gas feud but he did not fight the case. Or take Raytheon when it was fighting the Jindals. Raytheon had paid seven top lawyers a retainer fee of Rs. 2.5 lakh each just to ensure that the Jindals would not be able to make a proper case on a taxation issue. They miscalculated when a star lawyer fought the case at the last minute. “I don’t take negative retainers”, shrugs Rohatgi, former additional solicitor general. “A Lawyer’s job is to appear for any client that comes to him. lt’s not for the lawyers to judge if a client is good or bad but the court”. Indeed. He is, after all, the lawyer who argued so famously in court that B. Ramalinga Raju did not ‘fudge any account in the Satyam Case. All he did was “window dressing”.Some high profile cases have continued for years, providing a steady source of income, from the Scindia succession battle which dates to 1989, to the JetLite Sahara battle now in taxation arbitration to the BCCI which is currently in litigation with Lalit Modi, Rajasthan Royals and Kings XI Punjab.Think of the large law firms as the big Hollywood studios and the senior counsel as the superstar. There are a few familiar faces to be found in most of the big ticket cases, whether it is the Ambani gas case, Vodafone taxation or Bombay Mills case. Explains Salve, “There is a reason why we have more than one senior advocate on a case. When you're arguing, he’s reading the court. He picks up a point or a vibe that you may have missed.” Says Rajan Karanjawala, whose firm has prepared the briefs for cases ranging from the Tata's recent right to privacy case to Karisma Kapoor’s divorce, “The four jewels in the crown today are Salve, Rohatgi, Rohinton Nariman and Singhvi. They have replaced the old guard of Fali Nariman, Soli Sorabjee, Ashok Desai and K.K. Venugopal.” He adds, “The one person who defies the generational gap is Jethmalani who was India's leading criminal lawyer in the 1960s and is so today.”The demand for superstar lawyers has far outstripped the supply. So a one-man show by, say, Rohatgi can run up billings of Rs. 40 crore, the same as a mid-sized corporate law firm like Titus and Co that employs 28 juniors. The big law filik such as AZB or Amarchand & Mangaldas or Luthra & Luthra have to do all the groundwork for the counsel, from humouring the clerk to ensure the A-lister turns up on the hearing day to sourcing appropriate foreign judgments in emerging areas such as environmental and patent laws. “We are partners in this. There are so few lawyers and so many matters,” points out Diljeet Titus.As the trust between individuals has broken down, governments have questioned corporates and corporates are questioning each other, and an array of new issues has come up. The courts have become stronger. “The lawyer,” says Sundaram, with the flourish that has seen him pick up many Dhurandhares and Senakas at pricey art auctions, “has emerged as the modern day purohit.” Each purohit is head priest of a particular style. Says Karanjawala, “Harish is the closest example in today's bar to Fali Nariman; Rohinton has the best law library in his brain; Mukul is easily India's busiest lawyer while Manu Singhvi is the greatest multi-tasker.” Salve has managed a fine balancing act where he has represented Mulayam Singh Yadav and Mayawati, Parkash Singh Badal and Amarinder Singh, Lalit Modi and Subhash Chandra and even the Ambani brothers, of course in different cases. Jethmalani is the man to call for anyone in trouble. In judicial circles he is known as the first resort for the last resort. Even Jethmalani’s junior Satish Maneshinde, who came to Mumbai in I993 as a penniless law graduate from Karnataka, shot to fame (and wealth) after he got bail for Sanjay Dutt in 1996. Now he owns a plush office in Worli and has become a one-stop shop for celebrities in trouble.Which of the following is not true about Ram Jethmalani?
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MCQ-> I want to stress this personal helplessness we are all stricken with in the face of a system that has passed beyond our knowledge and control. To bring it nearer home, I propose that we switch off from the big things like empires and their wars to more familiar little things. Take pins for example! I do not know why it is that I so seldom use a pin when my wife cannot get on without boxes of them at hand; but it is so; and I will therefore take pins as being for some reason specially important to women.There was a time when pinmakers would buy the material; shape it; make the head and the point; ornament it; and take it to the market, and sell it and the making required skill in several operations. They not only knew how the thing was done from beginning to end, but could do it all by themselves. But they could not afford to sell you a paper of pins for the farthing. Pins cost so much that a woman's dress allowance was calling pin money.By the end of the 18th century Adam Smith boasted that it took 18 men to make a pin, each man doing a little bit of the job and passing the pin on to the next, and none of them being able to make a whole pin or to buy the materials or to sell it when it was made. The most you could say for them was that at least they had some idea of how it was made, though they could not make it. Now as this meant that they were clearly less capable and knowledgeable men than the old pin-makers, you may ask why Adam Smith boasted of it as a triumph of civilisation when its effect had so clearly a degrading effect. The reason was that by setting each man to do just one little bit of the work and nothing but that, over and over again, he became very quick at it. The men, it is said, could turn out nearly 5000 pins a day each; and thus pins became plentiful and cheap. The country was supposed to be richer because it had more pins, though it had turned capable men into mere machines doing their work without intelligence and being fed by the spare food of the capitalist just as an engine is fed with coals and oil. That was why the poet Goldsmith, who was a farsighted economist as well as a poet, complained that 'wealth accumulates, and men decay'.Nowadays Adam Smith's 18 men are as extinct as the diplodocus. The 18 flesh-and-blood men have been replaced by machines of steel which spout out pins by the hundred million. Even sticking them into pink papers is done by machinery. The result is that with the exception of a few people who design the machines, nobody knows how to make a pin or how a pin is made: that is to say, the modern worker in pin manufacture need not be one-tenth so intelligent, skilful and accomplished as the old pinmaker; and the only compensation we have for this deterioration is that pins are so cheap that a single pin has no expressible value at all. Even with a big profit stuck on to the cost-price you can buy dozens for a farthing; and pins are so recklessly thrown away and wasted that verses have to be written to persuade children (without success) that it is a sin to steal, if even it’s a pin.Many serious thinkers, like John Ruskin and William Morris, have been greatly troubled by this, just as Goldsmith was, and have asked whether we really believe that it is an advance in wealth to lose our skill and degrade our workers for the sake of being able to waste pins by the ton. We shall see later on, when we come to consider the Distribution of Leisure, that the cure for this is not to go back to the old free for higher work than pin-making or the like. But in the meantime the fact remains that the workers are now not able to make anything themselves even in little bits. They are ignorant and helpless, and cannot lift their finger to begin their day's work until it has all been arranged for them by their employer's who themselves do not understand the machines they buy, and simply pay other people to set them going by carrying out the machine maker's directions.The same is true for clothes. Earlier the whole work of making clothes, from the shearing of the sheep to the turning out of the finished and washed garment ready to put on, had to be done in the country by the men and women of the household, especially the women; so that to this day an unmarried woman is called a spinster. Nowadays nothing is left of all this but the sheep shearing; and even that, like the milking of cows, is being done by machinery, as the sewing is. Give a woman a sheep today and ask her to produce a woollen dress for you; and not only will she be quite unable to do it, but you are likely to find that she is not even aware of any connection between sheep and clothes. When she gets her clothes, which she does by buying them at the shop, she knows that there is a difference between wool and cotton and silk, between flannel and merino, perhaps even between stockinet and other wefts; but as to how they are made, or what they are made of, or how they came to be in the shop ready for her to buy, she knows hardly anything. And the shop assistant from whom she buys is no wiser. The people engaged in the making of them know even less; for many of them are too poor to have much choice of materials when they buy their own clothes.Thus the capitalist system has produced an almost universal ignorance of how things are made and done, whilst at the same time it has caused them to be made and done on a gigantic scale. We have to buy books and encyclopaedias to find out what it is we are doing all day; and as the books are written by people who are not doing it, and who get their information from other books, what they tell us is twenty to fifty years out of date knowledge and almost impractical today. And of course most of us are too tired of our work when we come home to want to read about it; what we need is cinema to take our minds off it and feel our imagination.It is a funny place, this word of capitalism, with its astonishing spread of education and enlightenment. There stand the thousands of property owners and the millions of wage workers, none of them able to make anything, none of them knowing what to do until somebody tells them, none of them having the least notion of how it is made that they find people paying them money, and things in the shops to buy with it. And when they travel they are surprised to find that savages and Esquimaux and villagers who have to make everything for themselves are more intelligent and resourceful! The wonder would be if they were anything else. We should die of idiocy through disuse of our mental faculties if we did not fill our heads with romantic nonsense out of illustrated newspapers and novels and plays and films. Such stuff keeps us alive, but it falsifies everything for us so absurdly that it leaves us more or less dangerous lunatics in the real world.Excuse my going on like this; but as I am a writer of books and plays myself, I know the folly and peril of it better than you do. And when I see that this moment of our utmost ignorance and helplessness, delusion and folly, has been stumbled on by the blind forces of capitalism as the moment for giving votes to everybody, so that the few wise women are hopelessly overruled by the thousands whose political minds, as far as they can be said to have any political minds at all, have been formed in the cinema, I realise that I had better stop writing plays for a while to discuss political and social realities in this book with those who are intelligent enough to listen to me.A suitable title to the passage would be
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