Friday 29 June 2012

APPSC GENERAL SCIENCE BIT BANK


GENERAL SCIENCE BIT BANK

The removal of water from the plants in the form of liquid droplets is called Guttation.

Headquarters of the World Meteorological Organisation is located at Geneva.

The native place of groundnut is Brazil.

Kisan Day is celebrated on 23rd December.

Central institute of Sub-tropical Horticulture is located at Lucknow.

National Research Centre of Agro-forestry is located at Jhansi.

Blue green algae are used to supply nitrogen to paddy.

1st dwarf rice variety developed in India was IR-8.

‘Dapog’ method of rice nursery was developed in Philippines.

Pink revolution is related to Onion.

White tip of maize leaves indicates the deficiency of Zinc.

As per the WHO the safe noise level for a city is 45db.

Loss of memory is caused by the destruction of Cerebellum.

The main constituent gas of LPG is Butane.

The direction of vibration of particles with respect to wave direction in transverse wave is Right angle.

X-Ray is Electromagnetic wave.

Yellow spot occurs in Eye.

Mach number is the ratio of Velocity of sound and velocity of a body.

Bile is produced by Liver.

At 40 C, volume of a certain mass of water is minimum.

The source of hydrogen for carbon assimilation is NADPH2.

Many elements have non-integral atomic masses because their isotopes have non-integral masses.

Newton’s laws of motion are valid in Inertial frame of reference.

Light refractive index of glass in minimum for Red colour.

Red blood corpuscles have life of 4 months.

Concentrated HNO3 can be stored in container made up of Al.

If mass is increased by 2 times and velocity is increased by 3 times of a body then its momentum will be increased by 6 times.

Effect of increasing temperature on resistance of semiconductor is decreasing.

Apart from quinine, the herbal drug Arteether is also used to cure malaria.

Chilgoza’ is obtained from the seeds of a species of Pine.

One kilowatt-hour equals to 3.6 x 106 J.

The atoms, in which the number of protons is same but the number of neutrons is different, are known as Isotopes.

A fluorescent tube is preferred to an electric bulb because in a tube electrical energy is almost fully converted into light.

Vinegar is an aqueous solution of Acetic acid.

A jet engine uses the surrounding air for its oxygen supply and so is unsuitable for motion in space.

A rocket carries its own supply of oxygen in the gas form as fuel.

Enriched Uranium is Natural Uranium in which the component of radio active isotope U235 is artificially increased.

Semiconductor laser is used in a laser printer.

The inexhaustible source of energy of the stars is due to Conversion of Hydrogen to Helium.

The leaning tower of Pisa does not fall because the vertical line through the centre of gravity of the tower falls within the base.

One barrel of oil is equal to 158.6 liters (159 liters).

While lifting a bucket of water from a well, we feel that the bucket becomes heavier above the surface of water.

Nutraceuticals are products having Nutritional and medicinal effects.

The thermometer suitable to measure 20000 C is Total radiation Pyrometer.

A colour-blind man marries a normal woman. The features of colour blindness will appear in his Daughter’s Sons.

When soggy biscuits are kept inside the fridge for sometime they become crisp because Humidity inside the fridge is low and extra moisture is absorbed.

Marie Curie won her two different Nobel Prizes in the fields of Physics and Chemistry.

Soft drinks such as Colas contain significant quantities of Caffeine.

The glucose level in commonly expressed as Milligram per deciliter.

Most of the explosions in mines occur due to the mixing of Methane with Air.

As per the recently released data the warmest decade in the recorded history of 160 years is 2000-09.

Jonas E Salk in 1955 is credited with discovering anti polio vaccine.

At constant temperature if the pressure decreases, the volume of a given mass of a gas will increase.

The electromagnetic radiation that is emitted during radioactive disintegration is Gamma rays.

61.8% of human body is water by weight.

The walls of a music hall should absorb sound.

The constituents of compressed Natural Gas (CNG) principally are Methane and Ethane.

Strontium and Barium salts provide colors to fire works.

Aditya is a satellite to study the Sun.

Word lengths for supercomputer range up to 64 bits.

At 1600 F, the Fahrenheit temperature is double of centigrade temperature.

In weightlessness condition, the size of flame of a candle will remain same.

The minimum distance between the source of sound and reflecting surface to hear an echo clearly is 17 meters.

Bioremediation means Elimination of toxic pollutant from environment by organisms.

The sun is visible to us a few minutes before the actual sunrise because of Refraction of light.

In a capillary tube a fluid rises more as compared to water, it is due to Surface Tension of fluid is less than that of water.

Helium gas is mixed with oxygen for respiration by divers in deep sea.

Chemically ‘Plaster of Paris’ is Calcium Sulphate.

It two bubbles of soap of different diameter come in contact by a tube, then the smaller bubble will become more smaller and bigger will become more bigger.

The temperature of the filament of lighted electric bulb is generally 20000 C – 25000 C.

The names of endangered plants are enlisted in Red Data Book.

Power Pack Project is related with Electrification with solar energy in the remote rural areas.

Big Bang Theory is related with Origin of Universe.

Pituitary gland secretes the milk ejection hormone oxytosine.

The PH level of blood of a normal person is 7.35 -7.45.

The release of Gambusia Fish into Ponds and wells helps in controlling the mosquitoes.

Xenon is called Stranger Gas.

Rubies and Sapphires are chemically known as Aluminum Oxide.

A widely used musical scale called diatonic scale has seven frequencies.

Agent Orange is a weed killing chemical used by the US military in the Vietnam War.

A light emitting diode, usually called an LED is a semiconductor diode that emits in coherent narrow spectrum light when electrically biased in the forward direction on the p-n junction.

Blue LEDs are based on the wide band gap semi conductors GaN(gallium nitride) and InGaN( Indian Gallium Nitride).

Cobalt-60 is commonly used in radiation therapy, because it emits Gamma rays.

In the human body, the longest cell is known Liver Cell.

Nichrome is used to make electric heater coil.

The formation of fruit without fertilization is known as Parthenicarpy.

Root modules are commonly found in leguminous plants.

ALZHEIMERS disease is a disorder of the brain.

Chromosomes of the father will determine the sex of a child.

Hypermetropia or long sight can be corrected by using Concave lenses.

Hypoglycemia refers to low sugar level in blood.

The antibiotic Ampicillin is a semi synthetic drug.

Opium is a plant product obtained from dried latex.

Drying oils contain a fairly large proportion of unsaturated fatty acids.

In mirrors the back surface is coated with a thin layer of Silver.

When quick lime is added to water, heat is liberated.

H5N1 virus is contagious for human beings.

Metal present in blood is Iron.

Night photography and photography in mist and fog are possible using Infra-red radiation.

In digestion, proteins are converted into Amino Acids.

The minimum temperature at which a combustible substance catches fire is called ignition temperature.

Centre for DNA Finger printing is located at Hyderabad.

Cryogenic engines are used in Rockets.

Workers of paint industry are exposed to Lead Industry.

Nitrate is responsible for blue baby syndrome.

Athletes with higher proportion of Red fibers in their muscles are better equipped for swimming.

Stem cell has the ability to develop into any type of cell.

The approximate height of a geostationary satellite from the surface of the earth is 36,000 Kms.

Skin cancer is caused due to presence of excess Arsenic in water.

Silk is a protein fiber.

Ganymede is the largest satellite in solar system.

Microwaves have the highest frequency.

All enzymes are proteins but all proteins are not enzymes.

In electric supply lines in India, Frequency is kept constant.

The flavour of apples is mainly due to Benzaldehyde.

Freon used as refrigerants is chemically known as Fluorinated hydrocarbon.

German silver is an alloy of copper, Zinc & Nickel.

The tracking of people by trained dogs is based on the recognition of carboxylic acids in the sweat from feet.

Boiling point of water depends on atmospheric Pressure.

An Astronaut in outer space will observe sky as Black.

Cylindrical lenses should be used to correct the defect of ASTIGMATISM.

Infrared rays have the longest wave length.

Electron was discovered by Joseph Thomson.

The 1st thermionic valve was invented by J.A.Fleming.

A substance which readily forms colloidal solution in contact with water is called Hydrophilic colloid.

The Enzyme in whose presence glucose and fructose are converted into alcohol is Zymase.

Oxalic acid is manufactured using Sawdust.

The study of visceral organs is Splanchnology.

The science dealing with the study of teeth is Odontology.

The branch of biology dealing with the study of cells is known as Cytology.

The study of extinct animal is called Paleontology.

The medical term used for the sleeplessness is Insomnia.

The causative agent of Tuberculosis is Mycobacterium.

The enzyme that is present in the saliva of man is Amylase.

Blood cancer is otherwise called as Leukemia.

WLL stands for wireless in Local Loop.

Superconductors are those elements whose resistance falls almost to Zero at very low temperatures.

Suppose if we measure the time lapse between the two sunsets by sitting in the beach, from this we can estimate the radius of the earth.

Radio immunoassay (RJA) is a therapy used to detect antibodies and hormones present in the blood samples.

In a Laser all the atoms emit the light waves of same frequency, amplitude and phase.

The polymer used in making plastic crockery is Melamine.

Vulcanization of Rubber is carried out by adding Sulphur.

World Health Day is observed on April 7.

If the temperature of a place increases suddenly the relative humidity Decreases.

Diphtheria is caused by bacteria and spreads through faecal matter by houseflies.

In a living cell, the site of ribosome formation is Endoplasmic reticulum.

Carbon is the principal structural element of a living cell.

Chloroplast is considered as a cell with in a cell.

A kidney carries out the function in human beings similar to the one which Malpighian tubules perform in cockroaches and other insects.

A surge of Luteinizing hormone stimulates ovulation in human females.

Mildness of shaving cream is enriched by Potassium Carbonate.

The purpose of adding plasticizers in paint manufacturing process is that they provide elasticity to the film and minimize its cracking.

Graphite can be used as lubricant because it has low viscosity.

Muriate of Potash fertilizer is assimilated directly by the plant.

Cylindrical lens is used to remove astigmatism from human eye.

When an electric bulb breaks, the reason for a mild bang is due to compressed gases rush out suddenly.

Specific gravity remains same in all systems of units.

A test tube baby means Fertilization in Vitro and then transplantation in the uterus.

Tele text is flashing of the text of news and information on the TV screen.

The causative agent of Tuberculosis is Mycobacterium.

An aeroplane is able to fly because, Moving air can lift objects.

Deficiency of insulin causes Diabetes.

Boiling point of water in Fahrenheit scale is 2120 C.

The instrument used to measure an angle accurately is vernier bevel Protractor.

From Carbon with Silicon, phosphorus and Sulphur make an alloy of Steel.

The number of chromosomes present in the somatic cell of the human cell is 46.

Earthworm has a clitellum.

The acid which is secreted by the glands in the stomach wall is HCL.

Kidneys excrete water, fat and various catabolic wastes.

An optically plane surface reflects a beam of light as a parallel beam in one direction.

Water is used in car radiator because of its high specific heat capacity.

The trace metal present in insulin is Zinc.

The metal present in chlorophyll is Magnesium.

Dry ice is solid carbondioxide.

Cement containing excess amount of lime cracks during setting.

The vessel which carries the venous blood to the lungs for oxygenation is Pulmonary arteries.

Quinine, the commonly used drug to treat malaria, is obtained from stem bark of a plant.

Most of the fish do not sink in water because of the presence of Swim bladder.

Heavy alcohol consuming people generally die of Cirrhosis.

Chocolates can be bad for health because of a high content of Nickel.

The carbohydrate which is used in silvering of mirrors is Fructose.

In a nuclear reactor the material used for absorbing neutrons is cadmium.

Solder metal is an alloy of lead and tin.

When a child is born, its blood carries wastes for the 1st time.

Bone is used as a fertilizer because it contains the plant nutrient Phosphorus.

The energy of the Sun is mainly due to Nuclear Fusion.

Plants release energy during Photosynthesis.

The part of a plant from which turmeric obtained is Root.

Genes, the hereditary units, are located in the Chromosomes.

The oil which causes dropsy is Argemone oil.

Universal donors are people with the bold group ‘O’.

Aquatic animal with the most developed intelligence is Whale.

The blood vessel which carries oxygenated blood to the liver is Hepatic Artery.

Beta cells secrete Insulin.

In the human body, fats are stored in the Adipose tissue.

Blood does not clot in the blood vessels due to the presence of Fibrinogen.

The DPT vaccine is given to young babies to protect them from Diphtheria, Whooping Cough and Tetanus.

Haemophilia is a genetic disorder.

The blood vessel supplying blood to the kidney is the renal artery.

The organ which stores carbohydrates as glycogen in the human body is Liver.

Optic fibers are used in place of wire cables because they do not generate magnetic fields.

A device that converts images into Digital data that can be stored in a computer is a scanner.

The sparking of a diamond is due to total internal reflection of light.

In a diesel engine, the high temperature needed to ignite the fuel is achieved by compressing air in the cylinders.

Waves that are required for long distance wireless communication are radio waves.

The radiation initially produced in fluorescent tube is Ultraviolet.

Silver nitrate solution is kept in brown bottles in laboratory because bottles stop the passage of light through it.

Lead pencil contains Graphite.

Mitochondria contain enzymes for cellular respiration.

A seed is a ripened Ovule.

In the human body, Spleen secretes hormones as well as digestive enzymes.

Trypsin is an enzyme.

Alum is not present in cement.

Convex lenses are used for the correction of long-sightedness.

A transformer is used to increase or decrease AC voltage.

Food is cooked in a pressure cooker quickly because Boiling point of water increases.

The chemical name for Baking Soda is Sodium Bicarbonate.

Mist is caused by water vapors at low temperature.

The 1st computer language developed was FORTRAN.

The total number of vertebrae in a human being is 26.

The instrument that determines specific gravity of liquids is Gravimeter.

Joseph Lister discovered antiseptic Surgery.

Carbon, Hydrogen, Oxygen, Nitrogen are present in all proteins. Besides these four elements, Sulphur is also present in some proteins. Some times, there may be phosphorus and iron as well in a few proteins through they is never found abundantly.

Normal blood pressure of the human body is 80 mm Hg diastolic and 120 mm Hg Systolic.

In hospitals, the oxygen tube for respiration contains oxygen and Helium.

Solder is an alloy of copper.

Scientific research studies have revealed that tobacco smoke contains “carcinogens”, which are the main cause of cancer. These carcinogens include 7 types of polycyclic hydrocarbons along with a radioactive element. This radio active element is Zirconium.

The major cause of ailments due to malnutrition among most Indian children from the age group of 1-5 years is deficiency of protein.

Acid rain is caused by pollution of environment by Nitrous Oxide and Sulphurdioxide.

A biogas plant work to its maximum capacity when conditions are anaerobic and temperature 400 C.

Chemical composition of Pearl is Calcium Carbonate.

The complete conversion of glucose in the presence of oxygen into carbondioxide and water with release of energy is called Aerobic respiration.

The most abundant elements in earth’s crust are Oxygen and Silicon.

One well known example of parasitic protozoan is Plasmodium.

Atomic mass unit is a unit of mass used to express atomic and molecular weights equal to 1/12 of the mass of an atom of Carbon (c).

It has been found that excessive use of cellular phone is likely to cause cerebral malignancy.

Iron does not for amalgams.

The chemical used for removing air bubbles from the glass during its manufacture is Potassium Carbonate.

Cast Iron has got the highest carbon content.

The gas that gives benzene on passing through a red hot tube is Acetylene.

The information retrieval in a magnetic tape is always sequential.

A green leaf placed in a dark room is illuminated by red light. The leaf will appear Black.

Cholera is mainly a water-borne disease.

Rows of trees grown along the coastal areas to reduce the impact of cyclones are known as Mangroves.

The most effective pesticide for general use against most garden pests in Malathion.

Dialysis is the treatment given to a patient suffering from Kidney Problem.

The drug which reduces Blood pressure is obtained from Rauwolfia Surpentina.

Modern Forensic scientists are using a most recently developed tool, namely DNA Finger Printing.

Water from an artesian well flows up automatically due to Hydrostatic Pressure.

Mercury is a metal.

TCP/IP – Transfer control/ Internet Protocol.

Father of e-mail is Tomlinson.

Smog – Smoke + Fog.

The colour of Ozone gas is Light Blue.

The Ozone layer exists in Stratosphere.

SAN (Sino atrial node) is also called Pace Maker.

Transformers are of 2 types 1. Step up Transformer 2. Step down Transformer.

Electron was invented by J.J.Thompson in 1897.

Neutron was invented by Chadwick in 1932.

The colour of I2 is purple Black.

Artificial satellites are placed in Thermosphere.

Stainless steel contains Iron, Nickel and Chromium.

Alternating current is used in electroplating.

Periscope is used in Sub marines.

The smallest Enzyme is Peroxidase.

The largest Enzyme is Catalase.

The fastest enzyme is carbonic anhydride.

Methane is released from Rice Fields in the most prominent quantities.

Potassium is not a structural component of the Plant.

Misch metal is widely used in the manufacture of cigarette lighters.

In the human body, Cowper’s glands form a part of Reproductive system.

The percentage of lead in lead pencil in 0%.

The gas responsible for the swelling of bread in co2.

Helium is preferred over hydrogen for use in airships because Helium is less reactive.

Vinegar is a commercial name of Acetic Acid.

In Vulcanization process Rubber is hardened by adding Sulphur.

Most of the explosions in mines occur due to the mixing of Methane with air.

Blue Green algae can serve as a bio fertilizer for Rice.

The blood glucose level is commonly expressed as Milligram per deciliter.

Phytotron is a facility to grow plants under controlled conditions.

Nichrome is very hard and very ductile.

Insect resistant cotton plants have been genetically engineered by inserting a gene from a bacterium.

Soft drinks such as colas contain significant quantities of Caffeine.

A TV remote control unit use Microwaves to operate a T V set.

Hybridoma technology is a new biotechnological approach for commercial production of Monoclonal antibodies.

The sensation of fatigue in the muscles after prolonged strenuous physical work is caused by the accumulation of lactic acid.

Aluminum surfaces are often anodized. This means the deposition of a layer of Aluminum Oxide.

A small pouch containing silica gel is often found in bottles of medicine tablet or powder form because Silica Gel absorbs moisture.

The universal Law of gravitation was propounded by Newton.

The gravitational force with which the sun attracts the earth is the same with which earth attracts the Sun.

If the distance between the earth and the sun were twice, the gravitational force exerted on the earth by the sun would be 1/4th of what it is now.

The mass of a body is different from its weight because mass is a measure of the quantity of matter whereas weight is a force.

A body weighs maximum at poles.

A person weighs more in lift, which is accelerating upward.

If a body is taken from the earth to the moon its mass will remain the same but weight will be different.

A ball tied with a string to a rotating shaft revolves at uniform speed. As the shaft is suddenly brought to rest the string starts getting round the shaft with the angular velocity of the ball increasing.

One finds it more difficult to walk on ice than on a concrete road because the friction between the ice and the feet.

A sheet of paper can be pulled out quickly from under a glass of water without spilling the water. This phenomenon illustrates inertia.

A horse pulling a Tonga moves forward due to the force exerted by the ground on the horse’s feet.

When the velocity of a body is doubled, its momentum is doubled.

The work done in holding a weight of 20Kg at a height of 1 m above the ground is Zero.

When the speed of a body is doubled, its kinetic energy becomes quadruple.

Winding a watch is actually the process of storing Potential energy.

A long thread suspended from a fixed point, has a small mass swinging to and fro at its lower end. The Kinetic energy is maximum in the middle of the swing.

Conservation of energy means that energy can neither be created nor destroyed.

A person climbing a hill bends forward in order to increase stability.

The period of revolution of a geostationary satellite is 24 hours.

If an apple is released from an orbiting space ship, it will move along with the spaceship at the same speed.

The density of sea water increases as depth and salinity increase.

When as ship enters a sea from a river it rises a little.

A steel ball floats on mercury because the density of mercury is higher than that of steel.

Inside an aeroplane, flying at a high altitude normal atmospheric pressure is maintained by the use of air pumps.

Atmospheric pressure is measured with a barometer.

The atmosphere exerts enormous pressure on us. But we do not feel it because our blood exerts a pressure slightly more than that of the atmosphere.

On a barometer, mercury is preferred over water because mercury has high density and low vapour pressure.

An object weighs maximum in vacuum.

Four solid cubes of different metals, each one having a mass of one kg, are weighed in water Cube with minimum density weighs minimum.

A stone is thrown into a deep lake. As it sinks deeper and deeper into the water, the up thrust acting on it remains constant.

Raindrops are spherical due to surface tension.

When two mercury drops are brought into contact, they merge to form a bigger drop because liquids have a tendency to possess minimum surface area.

On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because cohesion of mercury is grater than its adhesion with glass.

The swing of a spinning cricket ball in the air can be explained on the basis of Bernoulli’s theorem.

A train goes past a railway station at a high speed. A young boy standing on the edge of the platform is likely to fall towards the train.

In a sprayer the liquid rises in the tube due to lower pressure at the upper end.

A football bounces when it falls on the ground because of its property of elasticity.

In cold countries alcohol is preferred to mercury as a thermometric liquid because alcohol has very low freezing point.

The science dealing with the study of phenomena at very low temperatures is known as cryogenics.

On heating a circular metallic disc with a circular hole at the centre, the diameter of the hole will increase.

When a certain mass of liquid is heated in a glass flask the liquid level falls first and then starts rising.

When a cube of ice floating on water in a beaker melts, the level of water in the beaker remains the same.

If water in a lake were to behave like other liquids, then in extremely cold weather it would freeze from bottom to top.

The temperature of the top of a frozen lake is 150 C. The temperature of the water in the lake in contact with the ice layer is 00 C.

Fish can survive inside a frozen lake because water near the bottom does not freeze.

When water is cooled from 8o  C to 00 C its volume decreases up to 4o C and then increases.

The best conductor of heat among liquid is mercury.

An iron hammer, lying in the Sun, appears much hotter than its wooden handle because iron is good conductor of heat.

A thermostat is a device for regulating temperature.

A Pyrex number does not crack when hot water is poured into it because Pyrex does not expand much on heating.

Woolens keep us warm in winter because they do not allow our body heat to escape.

The freezer in a refrigerator is fitted near the top so that it can cool the whole interior by setting up convection currents.

By the process of radiation, heat is transmitted from the filament of an evacuated electric bulb to the glass.

Hot coffee is poured simultaneously in four metallic tumblers painted outside with different types of paints. After some time, the coffee will be found coldest in the tumbler painted back.

Light coloured clothes are preferred in summer because light colors are poor absorbers of heat.

A cup of hot coffee loses heat if placed on a metal table in a room by the process of conduction, convection, radiation and evaporation.

In a cup, tea cools from 90o c to 80o c in exactly one minute. It will cool from 70o c to 60o c in more than one minute.

Drinks remain hot or cold for a long time in a thermo flask because of the presence of air, which is a bad conductor of heat, in between the double walls and silver coating on the inside of the double walls.

For a given liquid, the rate of evaporation depends on the temperature of the liquid, the temperature of air and the surface area of the liquid.

A little ether on the palm gives a cooling sensation because ether evaporates.

Water stored in earthenware cools because water oozing out of the pores evaporates.

During summer, we feel comfortable under a fan because it sets the air in motion, thereby increasing the evaporation of sweat.

Perspiration is maximum, when temperature is high and air is humid.

Scalding with steam is more severe than scalding by boiling water because steam contains more energy than boiling water.

One feels cold after a dip in sea water due to the evaporation of water on the body.

The surface of water in a pond remains cool even on a hot day because water evaporates at the surface and evaporation causes cooling.

The quantity of water vapour at atmosphere can hold increases with increase of temperature.

The hygrometer is an instrument to measure relative humidity.

The boiling point of water depends on atmospheric pressure.

It takes much longer to cook things in the hills than in the plains, because in the hills the atmospheric pressure is lower than that in the plains and therefore water boils at lower temperature.

Food is cooked faster in a pressure cooker because due to high pressure the boiling point of water is raised.

The cover of a solar cooker is made of glass because glass allows sunlight into the container but does not allow heat radiation out of it.

Light waves are different from sound wave in that light waves are electromagnetic but sound waves are not.

Infrared waves have the longest wavelength.

The layer of the atmosphere which reflects the radio waves back to the earth is called ionosphere.

Radio reception improves slightly during the night because sunlight affects radio broadcasts to some extent during the day.

Television signals cannot be received ordinarily beyond a particular distance due to curvature of the earth.

Radar is used for detecting and fixing the position of objects, e.g., aeroplane.

A small hole in the window of a closed room forms an inverted image of outside building on the opposite wall of the room. This happens because of the rectilinear propagation of light.

A lunar eclipse occurs when the earth comes between the sun and the moon.

A solar eclipse occurs, when the moon comes between the Sun and the earth.

Corona of the sun is visible during total solar eclipse.

The image of an object formed in a plane mirror is virtual.

The minimum length of plane mirror in which a person can see himself full length should be nearly half his height.

If you walk towards a plane mirror at a speed of 10cm/s then your image approach you at a speed of 20 cm/s.

If you stand in a room, where two adjacent walls are covered with plane mirrors, the total number of your images formed will be 3.

Concave mirror can be used to obtain the real image of an object.

Concave mirror can be used as a burning glass.

A dentist’s mirror is a concave mirror.

For the rear view, motorists use convex mirror.

The type of mirror used in the headlamps of cars is parabolic concave mirror.

When a pencil is partly immersed in water in a slanting position, the immersed portion appears bent towards the water surface.

The sun remains visible for some time after it actually sets below the horizon. This happens due to atmospheric refraction.

If there were no atmosphere, the length of the day would decrease.

The sun and moon appear elliptical near the horizon due to refraction.

The twinkling of stars can be partly attributed to atmospheric refraction.

A rainbow is formed by the dispersion and total interval reflection of light by water droplets.

After a shower of rain, a rainbow is seen opposite the sun.

When white light passes through a glass prism, it gets dispersed into colours because different colours have different speeds in glass.

Colours which cannot be produced by mixing other colours are primary colours.

The three primary colours are blue, green and red.

The part of the camera which is analogous to the retina in the human eye is film.

The accommodation of the eye is produced by the ciliary muscles.

In old age, people have to wear spectacles for reading and writing because they lose the power of accommodation.

The sky appears blue because the atmosphere scatters blue colors more than the others.

To an astronaut, the outer space appears black.

In upper space, astronauts can see stars during the day in all directions.

The sun appears deep orange-red before it sets because its light has to traverse a thicker atmosphere, therefore, other colours get scattered and do not reach us.

Soap bubbles show multiple colours when viewed in white light because of the interference of the reflected light.

The technique of recording and reproducing three dimensional images of objects is known as holography.

When a wave goes from one place to another, it transports energy.

The pitch (or shrillness) of a sound is determined by its frequency.

A woman’s voice is shriller than a man’s due to higher frequency.

The loudness of a sound wave is determined by its amplitude.

Sound travels at maximum speed in steel.

Sounds cannot travel through Vacuum.

Thunder is heard much after a flash of lightning is seen because light travels much faster than sound.

Mach number is used in connection with the speed of aircraft.

Echoes are produced due to reflection of sound.

A clearly separate echo of a sound is heard when the minimum distance of the reflecting surface from the source of sound is 17 mts.

The walls and ceiling of an auditorium are covered with fibrous material, such as glass fiber, to absorb sound and prevent echoes.

Bats can fly in the dark because they are guided by ultrasonic waves produced by them.

A police van sounding its siren is moving away from an observer. The pitch(shrillness) of the sound from the siren relative to its normal pitch is lower.

A device used for measuring the depth of the sea is called fathometer.

If a bar magnet, tied in the idle with a thread were suspended at the north pole of the earth, it would take a nearly vertical position with its north pole pointing downward.

The crackling sound, heard when dry hair is combed with a hard rubber comb, is due to small electric sparks.

A capacitor (condenser) is used in an electrical circuit to store electric charge.

Soft iron would be most suitable for making an electromagnet.

Nichrome wire is used as a heat element in many appliances because of its high resistivity and its inability of oxidation in air when red hot.

Electric motor converts electrical energy into mechanical energy.

The starting current of an electric motor is much grater than the current flowing after the motor reaches its normal running speed.

Energy conversations in a loudspeaker are electrical to mechanical to sound.

The device used for converting mechanical energy into electrical energy is called a dynamo.

In our houses we get 220 V ac. The value 220 represents effective voltage.

The advantage of AC over DC is that it can be transmitted over long distances with minimum power loss.

The function of fuse in an electrical circuit is to break the circuit in case of overloading or short-circuiting.

In an electrical circuit, a fuse is connected in the live wire.

If a fuse blows frequently, one should call an electrician.

The material used for a fuse wire should have low melting point.

One should not connect a number of electrical appliances to the same power socket because this can damage the domestic wiring due to over heating.

An electrical appliance is earthed to prevent shocks.

An electric bulb has a filament made of tungsten.

The filament of an electric lamp becomes white hot but the lead-in wires holding the filament are only slightly heated because they have very low resistance.

Air is completely removed from an electric bulb to prevent oxidation of tungsten filament.

When an electric bulb breaks, there is a mild bang due to the air rushing in to fill the evacuated space.

A common fluorescent tube contains mercury vapour at low pressure.

The effective radius of atom is 10-10 mts.

X-rays are produced when very high energy, electrons are stopped suddenly at a metal target.

The force between two protons (positively charged particles) is attractive or repulsive depending on the distance between them.

In the nucleus of Uranium-2354, there are a total of 235 protons and neutrons.

Phenomenon of spontaneous disintegration of a heavy nucleus is termed as radioactivity.

Gamma rays are produced during radioactive nuclear changes.

Gamma radiations are used for sterilizing food stuffs, controlling pests and cancer therapy.

Radio isotopes are radioactive.

Fission reaction takes place in a reactor as well as an atomic bomb.

Enriched Uranium means uranium that has been enriched in isotope Uranium-235.

The function of a moderator in a nuclear reactor is to slow down the secondary neutrons.

A breeder reactor is that which produces more fissionable material than it burns.

The enormous energy released in an atomic explosion is due to the conversion of mass into energy.

The process by which energy is generated in the Sun is the fusion of Hydrogen.

The astronomical unit (AU) is the mean distance from the centre of the Sun to the center of the earth.

Constellations appear to change their positions at different times of night because the earth rotates about its axis.

The star (other than the Sun) nearest to the earth is Proxima Centauri.

The nearest star (other than the Sun), which is visible to the naked eye is Alpha Centauri.

Light from the nearest star (other than the Sun) reaches the earth in 4.2 years.

The Pole star does not seem to move because it is in line with the earth’s axis of rotation.

Saturn has the prominent rings around it.

Mars is known as the red Planet.

The Planet closest to the Sun is Mercury.

The heaviest among the inner planets is the Earth.

Mercury and Venus do not have satellites revolving around them.

Jupiter has the maximum number of satellites.

The tail of a comet always points away from the sun due to solar radiation and solar wind.

Halley’s Comet was seen in 1910 and again in 1986.

We see only one side of the moon all the time because the period of rotation of the moon on its axis is equal to its period of evolution around the earth.

Solar cells are the source of electric energy in an artificial satellite.

Treads on the shoe soles are made to increase friction.

Broad wooden sleepers are placed below the rails to reduce pressure exerted by the train.

An apparatus used for locating submerged objects is known as Sonar.

An artificially satellite can be tracked very precisely from the earth by using Doppler Effect.

A GM counter is used for detecting radioactivity.

Stars appear to move from east to west because the earth is rotating from West to east.

On a clear night we can see nearly 3000 stars with naked eyes.

The Pole star is part of the Constellation Ursa Minor.

Planet Neptune has 13 known moons.

Heavenly matter landing on the earth’s surface is known as meteorite.

The moon has equal periods of rotation and revolution.

Weight of a person can be zero when he is falling freely or he is orbiting in a satellite.

Mountain roads wind up gradually and do not go straight up, because on winding roads less force is needed to overcome gravity.

For the same total weight and the same fuel supply, a multistage rocket is preferred over a single-stage rocket, because the final velocity achieved by a multistage rocket is higher.

The earth and the moon are about the same distance from the sun, yet on the average the earth is much warmer than the moon because the moon has almost no atmosphere.

There is no Doppler effect for sound when the source of sound moves at right angles to the line joining the source and the observer.

Watt is the unit of power.

Pascal is the unit of pressure.

Joule is the unit of energy.

Newton is the unit of Force.

A star with a mass of less than 1.4 solar masses will probably end its life as a white dwarf.

Phobos is the moon of the planet Mars.

Titan is the moon of the planet Saturn.

Miranda is the moon of the planet Uranus.

Ganymede is the moon of the planet Jupiter.

Rocks of Saturn are likely to float on water.

Ganymede of Jupiter is the largest moon.

If a proton and an electron are at equal distance from a positively charged plate, then, electron will move towards the plate with acceleration nearly 2000 times that of the proton.

Graphite is used as a lubricant in heavy machines.

Hydraulic brakes in automobiles work on Pascal’s principle.

A hydrogen filled balloon rises only if its total weight is much less than the weight of air it displaces.

A barometer can also be used for determining altitudes and weather forecasting.

Dasymeter is used to measure density of a gas.

Manometer is used to measure the pressure of a gas.

Cryometer is used to measure low temperatures.

X-rays are electromagnetic waves.

The light phenomenon taking place in a periscope is reflection and refraction.

Endoscope, used by doctors for examining the inside of a patient’s stomach, works on the principle of total internal reflection of light.

Ceramics can be made to behave as a superconductor at a temperature of about 100 K.

Silicon and Germanium are semi conductors.

In an electric bulb, a little nitrogen or argon in introduced at low pressure to prevent evaporation of the filament.

A device used for converting A.C into D.C is called Rectifier.

The faint illumination of dark side of the moon during a crescent phase is due to sunlight reflected by the earth.

Venus appears to be the brightest in the night.

The only planet on which the sun rises in the west is Venus.

The planet similar to our earth in mass, size, and density is Venus.

Ecliptic’ is the term used for the sun’s path in the sky during a year.

An egg sinks in tap water but floats in a concentrated solution of salt because the density of salt solution exceeds the density of egg.

In cold regions, where temperature may fall below 0o C, farmers fill their fields with water to protect their crops from damage because water has high specific heat capacity.

The part of the human eye which performs a function similar to that of aperture in a photographic camera is pupil.

The f-number in a photographic camera is equal to the focal length of the lens divided by the diameter of the aperture.

The inside of a photographic camera is coated black to avoid reflection of light.

A photoelectric cell converts light energy to electric energy.

The Hubble space telescope has fixed the age of the universe at 8-12 billion years.

In Newton’s third law, the action and reaction forces act on different bodies and are always equal.

As a spaceship moves from a higher to a lower orbit, its speed increases.

An astronaut on a space walk changes his direction by using a hand rocket.

The self- maneuvering unit used by an astronaut works on Newton’s 3rd law of motion.

Kepler proposed the laws of planetary motion.

Galileo discovered moons of Jupiter.

Copernicus proposed the Heliocentric theory.

Kepler discovered that planets travel in orbits which are elliptical.

As water freezes, its temperature does not change.

The pupil of the eye adjusts automatically for amount of light.

A fluorescent lamp and a television picture tube emit light by the phenomenon of fluorescence, which is caused by beam of electrons in television tube and ultraviolet rays in a fluorescent lamp.

The velocity of light and radio waves are similar.

Colour is related to frequency.

Ultrasonics is used for diagnosing abnormalities or diseases in human organs such as liver, pancreas, kidneys, and heart.

Ultrasonics is used for mapping underground structures for oil and mineral deposits.

A diagnostic technique commonly known as “Ultrasound” is based on recording echoes of extremely high frequency waves.

The frequency of a sound wave is related to its pitch.

In electric circuits, miniature circuit breakers (MCB) are preferred over fuses because after removing the over load, the MCB can be reset very easily by pressing a lever.

An electron microscope can be used for viewing structure of bacteria and viruses.

In Uranium-235, fission occurs when it captures a slow neutron.

Hydrogen bomb is based on the principle of uncontrolled fusion reaction.

A positron is an elementary particle.

A positron is an elementary particle having mass equal to that of an electron.

A positron is an elementary particle with a charge equal and opposite to that of an electron.

A positron is an elementary particle with a charge equal to that of a proton.

Radioactivity is a property of atomic nuclei.

As a metal brick. Thrown into a deep lake, sinks deeper and deeper, the buoyant force acting on it remains constant.

Butter floats in droplets on the surface of a hot soup. But when the soup cools, the droplets spread out to form a thin layer on the surface. This happens because surface tension of the soup increases on cooling.

On the moon, an astronaut cannot drink lemonade with the help of a straw because there is no atmosphere on the moon.

AM (amplitude modulation) radio waves bounce off the ionic layers in the atmosphere.

FM (frequency modulation) radio waves penetrate the ionic layers.

FM transmission is accomplished on a ‘line of sight’ basis.

A remote control gadget (for TV etc.) has in it a small transmitter that emits infrared signals.

A body would weigh more at the poles than at the equator because equatorial radius is greater than polar radius and also due to the rotation of the earth about its axis.

A stone tied at the end of a string is whirled in a circular orbit. If the length of the string and the velocity of the stone are doubled, the tension in the string is also doubled.

Cooling inside a refrigerator in not proper when a thick layer of ice deposits on the freezer because Ice is a bad conductor of heat.

Water is a highly effective coolant for a car engine because water has very high specific heat capacity.

All the colours on a TV screen are produced from red, green and blue.

A dynamo, which is said to generate electricity, actually acts as a converter of energy.

A neon sign emits red light which comes from a luminous gas at low pressure.

Electron and positron is the particle and anti particle pair.

In a stable nucleus the electrostatic force between protons is weaker than the nuclear force.

The critical velocity of an object falling in a viscous medium depends on the coefficient of viscosity of the medium, the weight of the object and the size of the object.

The failure of light to travel strictly in a straight line is known as diffraction.

Doppler Effect is applied to find out whether a star is approaching earth or receding away from it.

Doppler Effect is applied to find out the speed of rotation of the sun.

1 KB is equal to 1024 bytes and 1 MB is equal to 1000 KB.

A computer’s ‘clock-speed’ is measured in megahertz and gigahertz.

The working principle of a washing machine is centrifugation.

Endoscope and periscope devices are based on the phenomenon of total internal reflection.

If a person looks at a coin which is in a bucket of water, the coin will appear to be closer than it really is.

If a person under water looks at a coin above the water surface, the coin will appear to be at a higher level than it really is.

Barium in a suitable form is administered to patients before an X-ray examination of the stomach, because barium is a good absorber of X-rays and this helps the stomach to appear clearly in contract with the other regions in the picture.

Cobalt -60 is commonly used in radiation therapy because it emits gamma rays.

Low temperatures (Cryogenics) find application in space travel, surgery and magnetic levitation.

An ordinary light bulb has a rather short life because the filament wire is not uniform or bulb cannot be evacuated completely.

The mid-air swing of a spinning football can be explained on the basis of Bernoulli’s principle.

If the current flowing through a heater coil is doubled, the heat produced will become four times.

The working of Hovercraft, Helicopter, Rocket & Lawn Sprinkler are wholly or partially explained by using Newton’s third law of motion.

Water is a bad conductor of heat but a good conductor of electricity.

Light travels faster in air than in water.

The oxygen that keeps us alive is a product of photosynthesis that comes from water.






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