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