• Monday, 14 March 2011

    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 - what's the softest: Talc

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