Metal

Q.  Why cannot a copper wire be used to make elements in electric heater?

A.  Copper melts at 108.30C and forms a black powder on reacting with atmospheric oxygen. For heater elements a metal should have more resistance to produce heat.

Q.  Why is a metal tyre heated before it is fixed on wooden wheels?

A.  On heating, the metal tyre expands by which its circumference also increases. This makes fixing the wheel easier and therefore cooling down shrinks it; thus fixing the tyre tightly.

Q.  Why does the mass of an iron increase on rusting?

A.  Because rust is hydrated ferric oxide which adds to the mass of the iron rod. The process of rusting involves addition of hydrogen and oxygen elements to iron.

Q.  After which chemical element is Argentina named?

A.  Silver

Q.  Which metal is heavier, silver or gold?

A.  Gold

Q.  Which quality of iron ore is best based upon iron content?

A.  Magnetite, followed by hematite>Limonite>Siderite

Q.  Which metals are used to make electrical wires?

A.  Copper and Aluminium

Q.  Which metal is liquid at room temperature?

A.  Mercury

Q.  Which metals are poor conductor of heat and electricity?

A.  Mercury and Tungsten

Q.  Which metals are called soft metals?

A.  Sodium and Potassium

Q.  Which metals are used for making jewellery?

A.  Gold, Silver and Platinum

Q.  Which metal is highly reactive?

A.  Sodium

Q.  Which metals are not malleable and ductile?

A.  Zinc, Arsenic and Antimony

Q.  Which metals have low melting and boiling points?

A.  Sodium, Potassium and Mercury

Q.  Which metals have low densities?

A.  Sodium and Potassium

Q.  Which metals are best conductor of heat?

A.  Silver and Copper

Q.  Which metals are highly malleable metals?

A.  Gold and Silver

Q.  Which metals are called noble metals?

A.  Gold and Platinum

Q.  Which was the first metal to be used by man?

A.  Copper.

Q.  Which one of the following metals has the highest density?

A.  Platinum

Q.  The first metal used by man was

A.  Copper

Q.  Why do you heat a metal rim before fitting it to a wheel?

A.  By heating, the rim expands and fits easily over a slightly bigger radius than that of the rim. On being cooled it contracts and has a firm grip on the wheel.

Q.  How would you distinguish between welding and soldering?

A.  Welding is the joining of metals by raising the temperature of the metals to fuse them together by melting their ends. Soldering is the joining of metals with the help of an alloy called solder.

Q.  A metal tea-pot has an ebony handle. Why?

A.  Ebony being bad conductor of heat, the handle does not get hot.

Q.  What is a meteorite made of?

A.  Most meteorites contain at least some iron metal (actually an alloy of iron and nickel). You can see the metal shining on a broken surface. Iron meteorites are all metal, stony iron meteorites are about half metal, half stone, and stone meteorites contain small flecks of metal.

Q.  What's the only metal that's not a solid at room temperature?

A.  Mercury.

Q.  What process involves heating an ore to obtain a metal?

A.  Smelting.

Q.  What's the most malleable metal?

A.  Gold.

Q.  What substance nets recyclers the most money?

A.  Aluminum.

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Liquid

Q.  Why is it the boiling point of sea water more than that of pure water?

A.  Sea water contains salt, and other impurities which cause an elevation in its boiling point.

Q.  Why Does ink leak out of partially filled pen when taken to a higher altitude?

A.  As we go up, the pressure and density of air goes on decreasing. A Partially filled pen leaks when taken to a higher altitude because the pressure of air acting on the ink inside the tube of the pen is greater than the pressure of the air outside.

Q.  Why does milk curdle?

A.  Lactose (milk sugar) content of milk undergoes fermentation and changes into lactic acid which on reacting with milk protein (casein) form curd.

Q.  Why does milk turn sour?

A.  The microbes react with milk and grow. They turn lactose into lactic acid which is sour in taste.

Q.  A piece of chalk when immersed in water emits bubbles. Why?

A.  Chalk consists of pores forming capillaries. When it is immersed in water, the water begins to rise in the capillaries and air present there is expelled in the form of bubbles.

Q.  Ice wrapped in a blanket or saw dust does not melt quickly. Why?

A.  Both wood and wool are bad conductors of heat. They do not permit heat rays to reach the ice easily.

Q.  Why are water or mercury droplets always round when dropped on a clean glass?

A.  The surface of a liquid is the seat of a special force as a result of which molecules on the surface are bound together to form something like a stretched membrane. They tend to compress themolecules below to the smallest possible volume, which causes the drop to take a round shape as for a given mass he sphere has minimum volume.

Q.  Why does an ordinary glass tumbler crack when very hot tea or milk is poured in it?

A.  When a hot liquid is poured into a tumbler, the inner layer of the tumbler gets heated, it expandsbefore the outer layer and an unequal expansion of both layers causes the tumbler to crack.

Q.  Why is water from a hand pump warm in winter and cold in summer?

A.  In winter, the outside temperature is lower than that of water flowing out of the pump, and therefore, the water is warm. Whereas in summer, the outside temperature is higher than the water of the pump, and therefore, it feels cold.

Q.  Why does a swimming pool appear less deep than is actually is?

A.  The rays of light coming from the bottom of the pool pass from a denser medium (water) to a rarer medium (air) and are refracted (bend away from the normal). When the rays return to the surface, they form an image of the bottom of the pool at a point, which is little above the real position.

Q.  Why does blotting paper absorb ink?

A.  Blotting paper has fine pores, which act like capillaries. When a portion of blotting paper is brought in contact with ink, ink enters the pores due to surface tension (capillary action f liquids) and is absorbed.

Q.  Why does a small iron sink in water but a large ship float?

A.  The weight of water displaced by an iron ball is less than its own weight, whereas water displaced by the immersed portion of a ship is equal to its weight (Archimedes? Principle).

Q.  Why does ice float on water?

A.  The weight of the ice block is equal to the weight of the liquid displaced by the immersed portion of the ice.

Q.  Why does moisture gather outside a tumbler containing cold water?

A.  The water vapour in the air condenses on cooling and appears as droplets of water.

Q.  Why does kerosene float on water?

A.  Because the density of kerosene is less than that of water. For the same reason cream rises in milk and floats at the top.

Q.  Why is the water in an open pond cool even on a hot summer day?

A.  As the water evaporates from the open surface of a pond, heat is taken away in the process, leaving the surface cool.

Q.  Why cannot a petrol fire be extinguished by water?

A.  Water, which is heavier than petrol, slips down permitting the petrol to rise to the surface and continue to burn. Besides, the existing temperature is so high that the water poured on the fire evaporates even before it can extinguish the fire. The latter is true if a small quantity of water is poured.

Q.  When a needle is placed on a small piece of blotting paper which is place on the surface of clean water, the blotting paper sinks after a few minutes but the needle floats. However, in a soap solution the needle sinks. Why?

A.  The surface tension of clean water being higher than that of a soap solution, it cans support the weight of a needle due to its surface tension. By addition of soap, the surface tension of water reduces, thereby resulting in the sinking of the needle.

Q.  To prevent multiplication of mosquitoes, it is recommended to sprinkle oil in the ponds with stagnant water. Why?

A.  Mosquitoes breed in stagnant water. The larvae of mosquitoes keep floating on the surface of water due to surface tension. However, when oil is sprinkled, the surface tension is lowered resulting in drowning and death of the larvae.

Q.  Why does oil rise on a cloth tape of an oil lamp?

A.  The pores in the cloth tape suck oil due to the capillary action of oil.

Q.  How does ink get filled in a fountain pen?

A.  When the rubber tube of a fountain pen immersed in ink is pressed, the air inside the tube comes out and when the pressure is released the ink rushes in to fill the air space in the tube.

Q.  Why does ENO's salt effervesce on addition of water?

A.  It contains tartaric acid and sodium bicarbonate. On adding water, carbon dioxide is produced which when released into water causes effervescence.

Q.  Which cocktail consists of Tia Maria, Vodka and Coke?

A.  Black Russian

Q.  What is the syrup drained from raw sugar called?

A.  Molasses

Q.  What do the letters ABV stand for on a bottle?

A.  Alcohol by Volume

Q.  Which alcoholic spirit is derived from rye and juniper berries?

A.  Gin

Q.  What is the scientific name of soda water?

A.  Carbonic Acid

Q.  Why is it easier to swim in sea water than in river?

A.  Density of sea water is higher

Q.  Which non-metal is liquid at room temperature?

A.  Bromine

Q.  Why do water pipes, in hilly areas, often burst on a cold, frosty night?

A.  When water in the pipe freezes, it expands. So pipes break

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Invention / Discovery

Q.  Who discovered natural radioactivity?

A.  Hentry Bequeral

Q.  Hydrogen was discovered by?

A.  Cavendish

Q.  Who discovered Argon?

A.  Ramsay

Q.  Name the scientist who proposed pH value?

A.  Sorenson

Q.  Who discovered the Law of Gravitation?

A.  Sir Isaac Newton

Q.  Who discovered penicillin?

A.  Alexander Fleming

Q.  Who invented elevator?

A.  EG Otis

Q.  Who invented Radar ?

A.  Robert Watson Watt

Q.  Who discovered Florescence?

A.  Sir George Stokes

Q.  Who was the inventor of stainless steel?

A.  Brearley

Q.  Who invented television?

A.  John baird

Q.  Who invented the stethoscope and when?

A.  In 1816, the French physician Rene Theoplhie Laennec (1781-1826) introduced a perforated wooden cylinder which concentrated the sounds of air flowing in and out of the lungs, and described the sound which it revealed. The modern form of stethoscope, with flexible tubes connecting the earpieces to a circular piece placed against the chest, was developed later in the nineteenth century.

Q.  How did arithmetical numbers come into existence? Where was ‘zero’ invented?

A.  The arithmetical numbers, which are universal today, were first invented system in India. This is known as Hindu numeral system. It simplified calculations by marking the values of a number depend on its position as well as the number itself. In the number 444, the single figure 4 represents 400, 40 and 4, and the whole number is the sum of these values. In contrast, the Romans used symbols whose values were the same irrespective of their positions.

Hindu numeral system included a zero. So, zero was first invented in India. Zero revolutionised arithmetical calculations and the numeral system. It was adopted by the Arabs and then reached Europe as early as in 10th century.

Q.  Who invented insulin?

A.  Insulin is a very useful drug for diabetes and was discovered by the Canadian physician and Nobel price winner , Dr.Federik Grant Banting in 1921.

Q.  Magnifying glass was invented by

A.  Roger Bacon

Q.  Polio vaccine was invented by

A.  Jonas Edward Salk

Q.  Who discovered the Blood groups

A.  Karl Landsteiner

Q.  Television was invented by

A.  John L. Baird

Q.  Wireless Telegraph was invented by

A.  Marconi

Q.  Incandescent lamp was invented by

A.  Edison

Q.  X-Ray was discovered by A.  Wilhelm Roentgen Q.  Chloroform was invented by A.  J.Y. Simpson Q.  Who invented the practical Locomotive A.  Richard Trevithick Q.  Who invented Microprocessor A.  Ted Hoff Q.  Who invented dynamite? A.  Alfred Nobel Q.  What creature's fossilized leg bone did John Horner discover red blood cells in, in 1993? A.  A tyrannosaurus rex's. Q.  What suntan lotion was developed by Dr. Ben Green in 1944 to protect pilots who bailed out over the Pacific? A.  Coppertone. Q.  What was Friedrich Serturner the first to extract from opium and use as a pain reliever? A.  Morphine. Q.  What computer company was named after a founder's memories of spending a summer in an Oregon orchard? A.  Apple. Q.  What weapon did German gunsmith August Kotter unload on the world in 1520? A.  The rifle. Q.  What type of machine did 19-year-old French genius Blaise Pascal invent to help his dad do taxes in 1642? A.  An adding machine. Q.  What Benjamin Holt invention was good news to farmers in 1900? A.  The tractor. Q.  What landmark invention did Ts'ai Lun invent from bark and hemp in the second century? A.  Paper. Q.  What did "Art Fry invent after scraps of paper to mark tunes in his hymnal kept falling out? A.  Post-it Notes. Q.  What did Leonardo invent to check humidity while he worked on the Last Supper fresco? A.  The hygrometer. Q.  What country was the first to register a patent on polyester? A.  Briton. Q.  What "foot doctor" held over 300 patents? A.  Dr. Scholl. Q.  What 1947 invention by Bell Telephone Laboratories spawned pocket-sized radios? A.  The transistor. Q.  What disease prompted polio vaccine inventor Dr. Jonas Salk to come out of retirement in 1987? A.  AIDS. Q.  What was the occupation of cotton candy machine inventor William James Morrison? A.  Dentist. Q.  What Italian astronomer invented the thermometer in 1592? A.  Galileo. Q.  What did George Nisser invent after observing high wire performers bouncing on safety nets? A.  The trampoline. Q.  What century saw the invention of the shoelace? A.  The eighteenth. Q.  What name did George Eastman invent in 1888 because it was easy to memorize, pronounce, and spell? A.  Kodak. Q.  What innovative inventor's Dymaaxion car could carry eleven passengers, exceed 120 mph and get 30 miles per gallon in 1934? A.  Buckminster Fuller's. Q.  What type of structure did R. Buckminster Fuller patent in 1954? A.  The geodesic dome. Q.  What century saw Alexander Cummings issued the first patent for a flush toilet? A.  The eighteenth. Q.  What portable device did James Spengler invent in 1907, using a soap box, pillow case, a fan and tape? A.  The vacuum cleaner. Q.  What landmark invention eased farming chores for Sumerians in 3500 B.C.? A.  The plow. Q.  What food product did Hyppolyte Merge-mouries invent in 1868 by treating oils with hydrogen? A.  Margarine. Q.  What British second lieutenant got the idea to fill a canister shell with musket balls and a charge of gunpowder? A.  Sir Henry Shrapnel. Q.  Who averaged one patent for every three weeks of his life? A.  Thomas Edison. Q.  What kitchen invention took the top prize at the 1893 Chicago World's Fair? A.  The dishwasher. Q.  What company gave the world the first electric toothbrush? A.  Interplak. Q.  What Edwin Budding invention began changing the face of English landscapes in the 1820s? A.  The lawn mower. Q.  What invention for keeping cold air out of buildings in winter was patented by Theophilus Van Kannel in 1888? A.  The revolving door.

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Energy

Q. What cooking fuel is produced by heating wood without oxygen?
A. Charcoal.
Q. Which will yield the most BTUs of energy--a gallon of oil, a pound of coal or a gallon of gasoline?
A. A gallon of oil.

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Electronics

Q.  Why are fuse provided in electric installations?

A.  A safety fuse is made of a wire of metal having a very low melting point. When excess current flows in, the wire gets heated, melts and breaks the circuit. By breaking the circuit it saves electric equipment or installations from damage by excessive flow of current.

Q.  What is ESP?

A.  ESP means extra sensory perception, i.e., perception or communication outside of normal sensory activity, as telepathy and clairvoyance.

Q.  Who is the Father of electricity

A.  Michael Faraday

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