Punjab State Exams

The first step along the path to modern mining began about two and a half million years ago when humans first started using stone tools. Although stones would have been collected from the Earth's surface initially, there is evidence for some form of flint mining as early as one million years ago. Early mining was extremely slow and labor- intensive. Although the discovery of metal and, much later, the introduction of explosives eased the process, the holes for the explosives still had to be made using hammers powered solely by brute force in order to drive a drill into the rock. By the mid-1800s, efforts to develop a mechanical rock. drill had begun in earnest, not only to Increase the efficiency of the mining industry but also to help build tunnels for the first railways. In 1871 Simon Ingersoll (1818-1894) received a patent for his rock drill and, although not more...

Outline : Calm evening—telephonic call; visit to the hospital; Scene inside the hospital—enquiry room, operation theatre; X-ray room; unable to find friend's room ! I wandered all over the hospital; got direction; met  friend, A visit to a hospital is a very painful experience. Someone who is dear to you is either seriously ill or has met with an accident. He is in a state of complete helplessness. He needs immediate medical care and treatment. The very name, hospital reminds us of sickness, disease, pain and cry. One becomes sick and frozen when one has to go to a hospital. It was calm and peaceful evening. I was enjoying an interesting  programme on my TV. All of a sudden the telephone bell rang. I took the receiver. Someone from the other end was speaking that my bosom friend Ravi had met with a serious accident. He was now in the more...

"Believe me, you've got to get up pretty early in the morning if you want to get out of bed." Groucho Marx, American comedian and actor In early-twentieth-century San Francisco, William Murphy (1876-1959) found that he had a problem. He wanted to court a young opera singer from a good background, but he lived in a small one-room apartment with a bed taking up most of the floor space. Since it would not be proper to bring a young lady back to his bedroom, he began experimenting with pivoting beds to make his room respectable. He applied for his first patent in 1900 and formed the Murphy Wall Bed Company that year. The company is still in business today, and is the second oldest furniture company in America. In the earliest and most familiar Murphy beds, the bed flips up at the head to be stored in a closet. In more...

Dhiru Bhai Ambani, an embodiment of enterprise, determination and perseverance, was an exceptional human being and an outstanding leader. From a humble beginning he rose to such a height that really inspires everyone. It was he who built Reliance to be India's largest private sector firm. He was one of those rare men who worked, not just for money, but also for the satisfaction of building something for posterity. Dhiru Bhai was a great visionary whose visionary leadership helped in emerging the Reliance Group as the largest business conglomerate in India. It has achieved a distinct place in the global pantheon of corporate gaints. Today this group's turnover represents nearly 3% of India's GDP. He was a man who was far ahead of his times. His philosophy was "Think big, Think differently, Think fast, Think ahead, and Aim for the best". He was the inspiring force to the reliance team. more...

The early calculating instrument we know as the abacus—consisting of a wooden frame supporting wires or rods on which wooden beads slide from side to side—was developed in Mesopotamia from a flat, sand-covered, stone counting board on which pebbles were moved. This aid to calculation was in use long before the adoption of the Hindu-Arabic numeral system and can be adapted to any numeral base. The abacus has a huge advantage over counting on the fingers of the hand, simply because it can be used to record very large numbers accurately. The easiest type of abacus to understand is the modern Western version that uses a base often. Here each wire carries ten beads and represents a decadal unit, that is one, ten, 100, 1,000 and so on. A number, say 617,483, can be represented by positioning the respective number of beads, on each wire, against one side of the more...

"What's important is that they are not designer babies. They are not per feet babies." Lord Robert Winston Preimplantation genetic diagnosis (PGD) was a pioneering genetic test developed in the late 1980s to enable concerned parents to test for genetic disorders before they even got pregnant. British researcher Alan Handyside and his colleague Robert Winston(b. 1940) reported their new technique in 1989. It involved checking fertilized eggs for genetic disorders before they were implanted. Unaffected embryos were then implanted through conventional in-vitro fertilization (IVF) techniques. Before PGD was introduced, parents likely to pass on genetic disorders to their children had few options to prevent this. They could remain childless, adopt, or get pregnant with the risk of having to terminate apregnancy if genetic disorders were discovered. PGD allowed them to pick only unaffected embryos. The technique of PGD involves stimulating a woman's ovaries with hormones to increase egg production. The more...

Not everyone has their own award named after them. The Oskar Barnack award, given annually to photo journalists, was initiated in 1979tomarkthe hundredth anniversary of the birth of the man who invented the 35-mm still camera. Barnack (1879-1936) had the idea for it back in 1905, but it was not until 1913-1914, while he was working as head of development at the German camera company Leitz, in Wetzlar, Hesse, that he was able to transform his idea into reality. Traditional heavy plate cameras were cumbersome to use and required significant preparation before each shot. It was impossible to take a "quick snap" of anything. Barnack's camera was a tough metal box that could fit in a jacket pocket and used a new kind of film, adapted from Thomas Edison's 35-mm cine film. In 1914 Barnacktooka picture of a soldier who hadjust put up the Imperial Order for mobilization. This was more...

"Good iron is not hammered into nails, and good men should not be made into soldiers" Chinese proverb When people talk about iron, they generally mean wrought iron. This is one of three major materials whose base is iron ore—a common element that has the ability to combine with other elements and therefore occurs in many forms. In order to produce its wrought, or worked, variety, charcoal and ore are heated sufficiently to reduce iron oxide to iron without melting it. The final product contains slag and other impurities that keep it from corroding. First produced in around 2500 B.C.E, wrought iron is the oldest form of iron and gave the Iron Age its name. Its availability increased when blast furnaces proliferated throughout Western Europe in the fifteenth century, before its slightly younger relative, cast iron (the malleable form of which is nowadays used in pipes as well as machine and more...

"The Jacuzzi is to this generation what the drive-in movie was in the fifties." Mike Darnell, U.S. television executive As with so many inventions, the Jacuzzi®—the best- known brand of hot tub—was invented to fulfil la very practical need: in this case, the healthcare of a family member. The Jacuzzi family were Italian immigrants to the United States in the early 1900s who developed a strong company in the aviation industry, and then flourished by designing irrigation pumps. But it was not until 1948 that they began developing the technology that would make them world famous. Candido Jacuzzi (1903-1986) had a son who contracted rheumatoid arthritis and received hydrotherapy treatment in hospital. Wanting to bring his son home, he developed a hydraulic pump to replicate the boy's therapy, and for some years the pump was marketed as the J-300 therapeutic device. In 1968 third-generation family member Roy Jacuzzi developed the more...

Since the dawn of computers, people have wondered if they tan be made to show intelligence—to think in the way that humans think. Charles Babbage and Ada Lovelace first debated the question when they worked together to create the first computer in 1835. By 1950, U.S. mathematician Claude Shannon was busy trying to figure out how computers could play a good game of chess. On the other side of the Atlantic, Alan Turing published his paper "On Computing Machinery and Intelligence," which considered the thorny problem of how you could actually tell if a machine was intelligent or not. In 1955, John McCarthy, of Dartmouth College, New Hampshire, proposed a conference to study the issue of intelligence research. In his proposal, he used the phrase "artificial intelligence" for the first time, and an entire field of study was born The 1956 Dartmouth Conference is now known as the defining moment more...