J&K State Exams

"[Their] only movement is the dancing of their fingers over the keys of their curious machines..." Sarah Campbell, The Times (February 8, 2007) The German inventor Karl Drais (1785-1851) is most famous for inventing the draisine or "running machine," one of the earliest forms of mechanized transport and a precursor of the modern bicycle. But in 1830 he also invented a keyboard system for recording speech that developed into what we now call a stenotype or shorthand machine. A stenotype (also called shorthand) machine consists of a keyboard of twenty-two letters and numbers that the operator, or stenographer, can press simultaneously to spell out whole syllables, phrases, or words in one action—like playing chords on a piano. Stenographers spell out syllables phonetically, that is by their sound rather than spelling. Broadly speaking, the left-hand fingers are used to produce the initial consonant, the right hand produces the final consonant, and more...

"The wire clip for holding office papers together has entirely superseded the use of the pin." Business, March 1900 Steel wire was still a relatively new concept in the mid- nineteenth century when an American, Samuel Fay, patented a wire ticket fastener that he used to attach labels to garments in 1867. When Fay mentioned as an aside in his patent application that his fastener was also useful for. holding together sheets of paper, his simple triangular-design wire fastener had unwittingly become the world's first bent-wire paper clip. Prior to this, the straight pin was the preferred method of attaching labels to garments. The paper clip, a single length of wire bent at either end to create a simple cross, speeded up the fastening of labels and resulted in less damage to the item being tagged. The destiny of the paper clip, however, was not to be found in the more...

A cochlear implant is a surgically implanted electronic device that provides a sense of sound to a person who is profoundly deaf. It works by directly stimulating the auditory (hearing) nerves with electrical impulses. American William House (b. 1923) is credited with being the first surgeon to implant a cochlear-type device. In 1957 House saw an article by two French surgeons who had inserted an electrode into the auditory nerve of a deaf man and shown that he could perceive sounds when the nerve was stimulated. In 1961 House placed cochlear implants in three patients, who gained some benefits. After research into the best positioning of the electrodes, House created the first wearable implant in 1969. Despite hostile criticism and fears that electrical stimulation of the cochlea might destroy brain tissue or spread infections, by December 1984 cochlear implants had the U.S. Food and Drug Administration stamp of approval, and more...

“One tree-one life” is a slogan which can be seen inscribed and there. Both human beings and trees have been bound by a bond of association since ancient times. It is a common knowledge that carbon dioxide is released by man and is taken in by trees, while oxygen is released by trees which is needed by man. Trees supply food, furniture and shelter to man while the latter gives manure to trees, sow seeds, transplant them from place to place and water them. Man cannot live without corn, fruit, vegetable flowers and leaves. Trees cannot survive in the face of weeds from which man alone can save them. This indicates that both man and tree are dependent on trees, animals and people is responsible for a balanced eco-system. Trees are of much benefit clouds to us. Trees invite clouds and rain without which crops cannot be grown. They cool more...

"None of us can have as many virtues as the fountain pen, or half its cussedness." Mark Twain The invention of the modern fountain pen is really more a story of perfection than invention. In 1883, more than fifty years after the fountain pen was first invented, a New. York insurance broker, Lewis Waterman, was set to sign an important contract and decided to honor the occasion by using the standard ink-filled pen of the day. However, fountain pens were notoriously unreliable, especially in their capacity to regulate their ink flow, so when the pen spilled ink across the contract so that it could not be signed, Waterman decided to do something about it» Within a year Lewis Waterman had designed the world's first practical, usable, and virtually leak proof fountain pen. To regulate the flow of ink he successfully applied the principle of capillary action, with the inclusion of more...

Trees are man's oldest friends. They are with us since ages. We cannot do without them. They are useful for us in many ways. Everyone knows now that trees are valuable. Concern about environment has made us conscious about trees. But our forefathers also knew the value of trees. Trees provide people with food, fibres and medicines.  Throughout history, people have used wood to make tools, construct buildings and create works of art. Living trees are 1 as valuable to human kind as an the products because they help heavy  conserving natural resources. Tree; help conserve soil erosion and flood. The roots prevent soil from  being washed away by heavy  rains. Tree roots also help store water underground. Forests are the  and main factors of our environment's water-cycle. Today's atmosphere is highly polluted and there is more need for oxygen. Trees keep air clean. They evaporate water  taken from the more...

"A man who could invent a safety pin... was truly a mechanical genius..." New York Times Necessity is the mother of invention according to Plato, and this was certainly true for Walter Hunt (1796- 1859) and his most famous invention—the humble safety pin. This useful object is found in households across the globe; it even gained status as a fashion accessory, with the Punk movement of the 1970s. Walter Hunt was a New York mechanic who, in 1849, sat wondering how he could pay off a small debt. He spent around three hours twisting a length of wire in his fingers before he created the answer to his problems, the ubiquitous safety pin. Pins were by no means a new idea, having existed for centuries before Walter's twist on the design. However, his creation was unique as it provided a solution to the potential problem of pricking oneself with the more...

The combatant nations of World War II developed radar to detect enemy airplanes. They also noticed that they were picking up signals from raindrops, hailstones, and snowflakes. After the war these signals were used for weather forecasting. From 1948 weather radar was carried on aircraft to help the crew detect potentially hazardous cumulonimbus cloud systems. Weather radar stations transmit a directional, narrow beam of pulsed microwaves up toward the clouds, using an antenna that rotates and scans the sky. These microwaves typically have wavelengths of 1-10 centimeters, these lengths being about ten times the size of the raindrops, hailstones, and snowflakes they are aiming to detect. The falling particles scatter the microwaves and a return pulse is then picked up back at the radar station. Five things are measured. The-time taken for the pulse to travel to and from the scattering body gives the distance to the precipitation. The Doppler more...

While working for the U.S. defense contractor Sanders Associates, Ralph H. Baer [b. 1922) had for some years been pondering possible ways of playing games through a television set. In 1966 he sat down and, in four short pages, produced a document that he calls the "Magna Carta of video games." This document was to form the basis of the very first video game console. At first he produced his prototypes in his spare time, but as he-developed his ideas his employer realized that there might be big money to be made, so they Started to support his project. Baer's "brown box" appeared two years later in 1968. It featured seven games: table tennis, volleyball, handball, soccer, golf, checkers, and even target shooting, using the very first prototype light gun. The console made use of clear plastic "overlays" that were placed in front of the television to simulate scenery and more...

Prior to the seventeenth century, anyone intent on lighting a fire would first have had to find another fire. It was either that or return to antiquity and try to coax a flame by means of one of a variety of methods involving sticks or stones. By the eighteenth century fires were being started with convex burning glasses, but these were of no use if a fire had to be lit in the dark, or when there was no direct sunlight. The first pneumatic fire-lighter was invented in 1770. This device relied on rapid compression of gases to produce heat and the all-important flame. But it was not until the mid 1830s that the first practical fire- lighting lamp for use in the home became available. Just five years after German chemist Johann Dobereiner came up with his initial idea in 1832, 20,000 fire-lighting lamps were in use in England more...