PHYSICAL PROPERTIES PHYSICAL PROPERTIES • Theory of mutation was propounded by Hygo de Vries. • A theory of acquired character was given by Lamark. • Charles Darwin is famous for his theory of struggle for existence and survival of the fittest. • Sigmund Freud is called as the father of modern psychiatry and psychology. • Energy stored in stretched spring is Elastic Potential energy • Energy stored in fossil fuels is chemical energy • Radio waves are Electromagnetic waves • A.C voltage is analogue quantity • Optical fibers work on polarization of electromagnetic waves • Condenser is used to collect the charge • In diesel engine ignition takes place by compression • A radar uses radio waves to detect enemy aircraft • Law of floating bodies was given by Archimedes • Particle with +ve charge but mass equal to electron is positron • Nucleus of an atom has +ve charge. • Bosons are Photons and Mesons • There is no neutron in the atom of hydrogen • Quark is an atomic particle. Scientists think that proton and neutrons are themselves made of still smaller particles called quarks • Muttons are particles of atom • John Dalton, an English scientist, gave Atomic Theory in 1803 describing atom as the smallest unit of an element • Gas in children’ s balloon is Helium • Weight of electron = 9.1 x 10 power -31 kg • Charge on electron = 1.6 x 10 power -19 coulomb • Weight of proton = 1.66 x 10 power -27 kg • Charge on proton = 1.6 x 10 power -19 coulomb • A proton is 1836 times heavier than an electron • Ordinarily and atom is a neutral particle • Ernest Rutherford, a New Zealander, in 1908 discovered Atomic Nucleus • Speed of sound is faster in hot air than in cold air • Ultrasonic are sound waves of high frequency = 12000 cycles/sec and higher • Sound travels faster in moist air than in dry air • Sound travels more rapidly in solids • Maximum limit of sound beyond which a man can become deaf is 129 decibel • Audible sound is 20-20,000 cycles/second • Inaudible sound >20,000 cycles/second • Velocity of sound at 0 deg: C is 331.7 m/s • Echo can only be produces when the distance of the obstacle is at least 17 meters • When we hear a sound, its impressions remain in our ear for 1/10th of a second • Image persists for about 1/10th of second in our eye • For creating a persistence of vision, pictures are projected at the rate of 10 or more/sec • Nuclear Energy is not a source of alternative energy. • Videotape used in camcorders to record audio and video signal employee fine grains of iron oxide. • Temperature inside a refrigerator is 40 deg: F • The laws of reflection were first discovered by a al- Hazen • 0.200 grams are equal to one carat. • One million cycles per second is called Megahertz. • Carbon fiber is made by heating textile fibers. These are used in tennis rackets and racing yacht • Catalytic converter reduce the harmful fumes the engine emits • If you double the voltage you double the current (Ohm’s law) • What product uses the most silver-Camera Film • The speed of sound depends on the medium through which the waves are passing. The speed of sound in gases depends on what? Density • Two or more molecules of carbohydrates are linked together through glycosidic bond • peptide bond b\w amino acids, joined to form proteins, is the linkage b/w N and C • An android is any robot that: has the ability to make decisions and formulate plans • Semaphores were used between sailors for many years to communicate between ships • One of the first long distance communication system invented in 1790 was the semaphores towers • Telegraph was invented in 1821 • Telephone was invented in1876 • Us inventor Samuel More developed the system of dots and dashes of telegraph that was known as Morse Code • Scientist now think that protons and Neutrons are themselves made of still smaller particles called quarks. • Portable gadgets = Mobile phones and portable TVs. • Derailleur gears are used in Bicycles. • Motor – cross race is for motor cycles. • Cantilever brake used in Bicycle. • Speed of light 300,000 kilometers per second. • Engineers use electronic theodolite and range-finder to measure the distance and angle to calibrated staff. • Centigrade and Celsius temperatures are same below freezing point. • which instrument is used to measure pressure? Manometer • the velocity of light was first measured by Olaf Roemer • centigrade and fahrenheit scales gives same readings at 32 degrees • The first European scientist who refuted the belief that the earth was the centre of the universe was Copernicus. • Mobile phones transmit message using radio-type waves called microwaves • Super conductors are also strong diamagnetic this means they strongly repel magnets. • Super conductors are used in very fast computers and also in trains like Maglevs. • Electronic theodolite and range finder measures and distance and angle. • A fluorescent light is a glass tube containing gas which produces UV light when current passed trough it. Tube is coated with phosphor which glows when UV hits it. • Some of the chemicals from the recycle of old cells are used by liver to make bile which is stored in gall bladder. • Which is lighter, gold or plastic? Plastic • Lasers are a special source of light called coherent light this means all the light waves are in step with each other and travel in same direction • Laser produce light of one particular wavelength and it is s single, pure color. • The first hologram was make in 1962 • Laser = Light Amplification by Stimulated Emission of Radiation • Quartz-halogen bulbs are used in overhead projectors and spotlights • Helium is uses to fill airships and balloons • Helium is used to pressurize hydrogen fuel in rockets and the air in diver’s air tanks • Apart from radon, which is radioactive, the noble gases are used in lighting. • The noble gases have very low boiling points. • Liquid helium is the coldest substance. • A gas only becomes liquid at -268.9 deg: C • Combustion is a kind of oxidation reaction. • At room temperature the particles in air travel at around 1800 km/h the same speed as a bullet fires from a rifle. • Generators convert mechanical energy into electrical energy. • The principle behind the generator is electromagnetic induction. It was discovered by Michael Faraday. • Lovell telescope is at Jodrell Bank the site for space observatory • Nicolous Copernicus (1473-1543) was born in Poland and was the first to explain the solar system. • Derailleur gear are used in bicycles • Cantilever brake is also used in bicycles • Static electricity makes a balloon stick to the wall after you have rubbed it on your hair. • John Bardeen, Walter Brattain and William Shockley in 1947 used a semiconductor called germanium to make the world’s first transistor. • A diode conducts electricity easily in one direction but resists the flow of electricity in the other. • A capacitor stores electric charge. Capacitors are important components for making timers. • Capacitors are used in filtering circuits like treble and bass in hi-fi • Transistors can be used as logic gates • Energy value of food items is expressed in kilojoules (kj) or thousands of joules. • British scientist James Prescott Joule discovered the principle of conservation of energy. • Which one of the following statements regarding sound is true? Its source is always a vibrating material. • Weight of an object put in a satellite orbiting in space around the earth is reduced to zero • Movie camera take pictures at rate of 24 pictures per second • Density of water is 1 • Water expands as it freezes to ice. This makes ice less dense than water which causes ice to float. • Heat flows in three ways conduction, convection and radiation • A concave lens is used for the correction of the Hyperphobia • Silver metal has the highest electrical conductivity. • Mohr’s scale hardest substance is diamond - whats the softest: Talc
Posted on: Sat, 29 Mar 2014 07:13:23 +0000
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