Bihar State Exams

Superconductors are materials that have no electrical resistance, so electricity can flow through them with out any loss. The superconductivity phenomenon was first discovered in 1911 by researchers in Germany who used solid mercury as their conducting material. Superconductivity was at first seen only in certain substances when supercooled to temperatures close to absolute zero, or -459°F (-273°C)—the coldest temperature theoretically possible. In 1986 Georg Bednorz (b. 1950) and Alex Muller (b. 1927), both researchers at IBM, discovered a new type of superconducting material, copper oxide perovskites, that could superconduct at -396°F (-238°C). Paul Chu, at the University of Houston, improved on this by bringing the superconducting temperature up to a relatively balmy -296°F (-182°C). For the first time, superconductivity could be made to occur at temperatures in the range of liquid nitrogen. The discovery quickly led to a huge meeting of physicists in New York, a meeting that became more...

Superconductors are materials that have no electrical resistance, so electricity can flow through them with out any loss. The superconductivity phenomenon was first discovered in 1911 by researchers in Germany who used solid mercury as their conducting material. Superconductivity was at first seen only in certain substances when supercooled to temperatures close to absolute zero, or -459°F (-273°C)—the coldest temperature theoretically possible. In 1986 Georg Bednorz (b. 1950) and Alex Muller (b. 1927), both researchers at IBM, discovered a new type of superconducting material, copper oxide perovskites, that could superconduct at -396°F (-238°C). Paul Chu, at the University of Houston, improved on this by bringing the superconducting temperature up to a relatively balmy -296°F (-182°C). For the first time, superconductivity could be made to occur at temperatures in the range of liquid nitrogen. The discovery quickly led to a huge meeting of physicists in New York, a meeting that became more...

A precious child was born in 1469 in khatri family at Talwandi, near Lahore. The village is called Nankana Sahib which is now in Pakistan. The name of the boy was Nanak, known to the world as Guru Nanak Dev. At the age of seven he joined the village school.   He was very intelligent, and learned the alphabet in one day. Once he composed a beautiful hymn which is now in Guru Granth Sahib.   He used to think about God for hours together. When his father gave him twenty rupees to do some profitable business, he spent the money on feeding the hungry men. His father became worried about his work and approach towards life. So Nanak was married at the age of fourteen. But even marriage could not stop him from thinking about God. His father sent him to Sutanpur and was made a Government store-keeper by more...

In 1821 the Estonian physicist Thomas J. Seebeck made an accidental discovery: Not only does a potential (that is, voltage) difference exist between the two ends of an electrical conductor if these ends are at different temperatures, but also the voltage is a direct function of the temperature difference. If a circuit is made of a uniform material, the net loop voltage is zero. If, however, two different metallic conductors, such as platinum and palladium, are connected, a positive voltage is produced. The thermocouple, after being calibrated using the melting points of certain pure substances such as lead (621.68°F/327.6°C), silver (1,762°F/961°C), and nickel (2,647°F/1,453°C), can measure temperatures nearly up to the melting points of its two components. The Italian physicist Leopoldo Nobili (1784-1845) was slightly less ambitious and used a series of antimony bismuth bars to construct a thermopile in 1829. This was used to investigate infrared radiation and was more...

The Holi Festival is one of the most important and interesting festivals of Hindus. It comes in the Hindi month of Fagun. All persons young and old, men and women, boys and girls look forward to this  a day with great joy. There is a story.about the origin of this festival. Prahlad was a devotee of Vishnu. His father Hirnakashyap, hated Vishnu. He wanted to punish his son for chanting the name of Vishnu. He tried many ways to kill him but all failed. Hirnakashyap was determined to kill him. In the end he asked his sister, Holika to enter the fire with Prahlad. Her body was fire proof. Fortunately, Prahlad came out of the fire safe but his paternal aunt (Holika) was burnt to death. So this festival is celebrated in honour of this event. It is also said that the Holi is the beginning of the harvest season. more...

In 1797, Robert Fulton (1765-1815), a Pennsylvania- born artist and inventor, offered to build a submarine for the French, who were then engaged in a bitter war with Britain. He proposed to use the vessel to sink Royal Navy warships blockading French ports. The French government hesitated to become involved in what they regarded as a dishonorable style of warfare. Undeterred, Fulton went ahead with developing his machine, gaining French financial backing after Napoleon made himself First Consul in 1799. Fulton's "mechanical Nautilus" was launched on the River Seineat Rouen in 1800. Its inventor described it as "six and a half meters long and two meters wide... built entirely of wood." It had a mast and sail for propulsion on the surface, which were lowered when it submerged by filling its water tanks. The crew of two to four could stay underwater for around four hours thanks to a supply more...

"[The Hamilton Beach drink mixer] became as much a tradition as hot dogs, apple pie, or baseball." Goodman's online shopping catalog Chester Beach grew up on a Wisconsin farm, and it was there that his natural aptitude for repairing and fixing machinery was nurtured. He met his future business partner L. H. Hamilton, when they were both working at an electrical motor company in Wisconsin in the early 1900s. Realizing their potential for a profitable future, the pair formed the Hamilton Beach Manufacturing Company. What made the company so successful was essentially Beach's invention of a high-speed, lightweight universal motor. The motor was able to safely and consistently achieve up to 7,200 revolutions per minute and its ability to run on both AC (alternating current) and DC (direct current) meant that it was extremely adaptable. The motor was used in their food mixer—which was a huge success for the company—and more...

“What have you done with my child [the radio broadcast]? You have debased this child..." Lee De Forest, Chicago Tribune (1946) In 1904, British physicist-John Ambrose Fleming (1849-1945) developed what he called an "oscillation valve." Later rechristened the "diode," it Is universally recognized as the first true electronic device. Two years later, building on Fleming's work, American electrical engineer Lee De Forest (1873-1961) created the Audion vacuum tube—the first valve amplifier. De Forest's major innovation was in creating a valve that would not only rectify the AC current, but boost it. The Audion contained the same filament, cathode and plate/anode design of the Fleming valve, but placed between them was a zigzag of wire called a grid. A small electric current applied to the grid would result in much current shifting from the filament to the plate. Thus was born the first electrical amplifier. With its three active electrodes, De more...

A horse is one of the most faithful animals. In ancient times, horses were very popular with kings. They were used in the battle field that saved their masters' lives at the cost of their own. It was commonly used as a means of transport in the past when there were no buses and trains. Presently, a horse is used for riding, drawing carts. handsome domestic animal, it is found all over the world, but Arabian horses are the best. A horse may be of various gray or a mixture of different shades. It has four strong legs. Its hoofs are not parted in the middle like those of a cow. There is thick black hair in its tail. It has a mane on its neck. Its ears are very large. A horse eats green grass, straw, food grains and leaves. Without proper training, a man cannot ride on the more...

The idea of creating a man-made diamond is a very appealing one—a kind of alchemy (the process of turning base metal into gold), but one that is, remarkably, achievable. Synthetic diamonds actually come in two kinds—simulant (which are diamond-like in looks and structure) and synthetic, where the chemical structure of the stone is also the same. The latter is a "true" synthetic diamond. Simulant diamonds made from silicon carbide were first discovered by Henri Moissan in a meteorite crater in 1893.They were later reproduced by him and others in the lab, most fampusly Willard Hersey, whose diamond can still be seen at the McPherson Museum in Kansas. It was not until 1953, however, when a team led by Baltzar von Platen (1898-1984), working in secret for the Swedish electrical company ASEA, actually succeeded in generating sufficient heat and pressure to create the first synthetic diamond. Their machine generated 83,000 atmospheres more...