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