CBSE PHYSICS
Acupuncture—It is an ancient technique, very much in vogue in China, of deadening pain. It is claimed that by the use of acupuncture major surgical operations can be performed without anaesthesia. The underlying principle is that there are several points in the body at which if needles are struck, a numbing effect is produced.
Allometry—It denotes the relationship between the growth rates of an individual plant part/or an organ/or organism.
Allotropy—Existence of a chemical element in two or more forms differing in physical properties but giving rise to identical chemical compounds.
Allelopathy—Also known as antibiosis of allelochemical interaction, which has direct or indirect inhibitory influence of one plant species or others and V/s.
Anabolism—Building up of complex substances from simple ones in living tissues. It is a part of the process of metabolism.
Anaesthetics—Drugs causing unconsciousness such as chloroform.
Antibiotics—These are the drugs which are produced by bacteria and which act against other strains of bacteria e.g. Penicillin, Streptomycin, Teramycin, Chloromycetin etc.
Astigmatism—It is an aberration of an optical system that causes lines in some directions to be focussed less sharply than lines in other directions. To the eye it causes defective vision.
Atomic Energy—It is produced due to the splitting up of atoms of certain radio-active elements. The energy produced in this manner can be used for constructive or destructive purposes.
Atomic number—The number of electrons, or what is equivalent, the positive charge on the nucleus, of an atom.
Black box—It is an apparatus which records the flight data of an aeroplane and is also a voice recorder.
Bacteria—Are minute organisms appearing under a microscopic observation as a group of rods or spheres. Some are harmful bacteria for they help in the spread of disease, some are useful for making soil fertile.
Bioeco compass—A unique device developed by Timiryazev Agricultural Academy in Moscow, which can give reliable forewarning of natural calamities like floods and droughts.
Blood group—Dr. Costello and later Dr. Moss classified blood into various groups viz. AB, A and O according to the viscosity of blood. Patients are administered blood of their own group.
Blood Transfusion—This is process of transfusing blood of one person into the blood stream of another person.
Calorie—The amount of heat needed to raise the temperature of 1 gram of water through 1ºC.
Centripetal Force—The force which tends to pull whirling objects towards the centre of rotation.
Catalyst—A substance which aids or speeds up a chemical process, without itself undergoing any change.
Chemotherapy—Treatment of diseases by means of a chemical compound having a specific bactericidal effect.
Chlorophyll—The green pigment contained in the leaves of plants. It enables the plants to manufacture food with the help of sun light. It was first discovered by P.J. Pelletier (1778-1892) and J.B. Caventon (1715-1887) in 1818.
Colour Blindness—It is an inborn condition in some people of not being able to distinguish between certain colours.
Deficiency diseases—These are the diseases which are caused due to the deficiency in the body of certain vitamins.
Dialysis—It is a machine used for blood purification when the kidneys malfunction. The process is also known as dialysis.
Dry Ice—It is solid carbon dioxide.
Efflorescence—The property possessed by certain crystalline substances of losing their water of crystallization when exposed to the air and becoming amorphous. Example—washing soda.
Electric Motor—It is a device to transform electrical energy into mechanical energy.
Electrolysis—It is the passage of an electric current through an electrolyte with subsequent migration of ions to the electrodes.
Ecology—It is the study of the balance of nature, how different living beings and inanimate objects function together as a harmonious whole.
Endemic—A disease which becomes prevalent in a particular area on account of its sorrounding conditions.
Enzymes—These are organic catalysts which actually accelerate the chemical reactions occurring in the living organism. For example lipase accelerates the hydrolysis of fats; diastase helps the conversion of starch to glucose; zymase quickens fermentation of sugar to alcohol.
Epidemic—A disease which attacks many people in a particular area at one time.
Escape Velocity—It is the minimum speed which a space craft must have to escape the earth’s “Gravitational Pull”. It is 11•2 km/sec. from the earth.
Exbiology—The new science which deals with life or possibilities of life existing beyond the earth i.e. on other planets.
Fossils—The remains or forms of a plant or animal which are found deposited at a particular place over a long period of time in the form of rocks.
Flyash—A waste product from thermal power stations using coal. The strategic metal., germanium can be extracted from flyash.
Fungi—A class of plants which have no chlorophyll.
Gene—An elementary unit of heredity. It occurs along the length of the chromosomes which surround the nuclei.
Genetic Code—The code of life by which inherited characteristics are handed down from one generation to another. The code bearing material is…D.N.A. (deoxyribonucleic acid) a biological matter which makes transmission of characteristics possible.
Green House (Glass House)—Heating influence by solar radiation reaching ground surface, allowed by CO2, ozone, dust, water, vapours, atmosphere etc.
Haemoglobin—The red pigment present in the blood functioning as an oxygen carrier.
Hibernation—Condition of sleep during certain parts of the year.
Hormones—These are chemical substances produced by ductless or endocrine glands.
Heavy water—The usual chemical formula for water is H2O.
Hydrophobia—It is usually caused by the bite of a mad dog. It is an incurable disease. Once it develops, the patient dies of it. It can be prevented by injections discovered by Pasteur. Injections are known as ARV (Anti-rabic venom).
Hydroponics—It is the process of growing plants by feeding them on nutrients without using soil.
Implosion—It is a technique for detonating underground nuclear devices.
Ionisation—It is the process of splitting up of a molecule into ions.
Iron Lung—A mechanical device consisting of a chamber in which alternate pulsations of high and low pressure of the thorax of a patient produce normal lung movements. It is used in cases in which respiration muscles are paralysed, e.g. in poliomylitis.
Isotopes—Atoms of the same element with the same atomic number but with different atomic mass number are known as Isotopes of that element. They contain different number of neutrons.
Kinetic energy—It is the energy possessed by the body by virtue of its motion.
Laser Beam—‘Laser’ is the abbreviated form of ‘Light, Amplification, by Stimulated Emission of Radiation’. It is a device for producing concentrated, powerful monochromatic and coherent beam of light. It is used in medicine, warfare etc.
Light Year—An astronomical measure of distance; the distance travelled by light in vacuum in one year. The velocity of light is, 3 x 108 m/s (1 light year = 9•46 x 1015 m)
Meson—A new particle which holds the protons and neutrons of the atomic nucleus discovered by a Japanese scientistYukawa.
Metabolism—It is a chemical process concerned with the burning and regeneration of tissues occurring in living organisms.
Myopia—Short-sightedness. A myopic man cannot see distant objects clearly while he can see near objects quite clearly.
Nitrogen Fixation—Nitrogen has the property of reacting under special conditions to form a number of useful products. Owing to this property the free atmospheric nitrogen is converted into so many nitrogenous compounds.
Neutralization—Addition of acid to alkali or vice-versa, so that the solution is neutralized, the properties of the compounds disappear.
Neutron Bomb—Developed by the United States, the bomb causes negligible damage to buildings and other installations, but kills people instantly through radiation.
Nuclear Fission—It is the process of breaking apart of the nucleus of an atom.
Nuclear Fuel—It is a substance which undergoes nuclear fission in a nuclear reactor.
Osmosis—In the process of a solution being separated from its pure solvent by a semi-porous membrane, the molecules of the solvent begin to travel across the membrane and reach the solution to dilute it. The process goes on till concentration is equal on both sides of the membrane. This phenomenon is known as Osmosis.
Outer space—The part of the universe which lies beyond the earth’s atmosphere where the density of matter is very low.
Oxidation—It is a process of addition of oxygen.
Photosynthesis—It is the process by which green plants manufacture food in the form of carbohydrates in the presence of sunlight.
Polymerization—Chemical union of two or more molecules of the same compound to form larger molecules. The process results in the formation of a new compound of the same empirical formula but greater molecular weight.
Potential energy—It is the energy possessed by the body by virtue of its position or shape.
Protoplasm—It is the living matter present in the cells of animal and vegetable life.
Psychedelic drugs—These are the drugs which produce a mental state of great calm.
Radiation—The process of transmission of heat in straight lines without heating the intervening medium.
Radio activity—It is a characteristic of substances like uranium, thorium, radium and actinium to emit radiation which can penetrate opaque substances, affect a photographic plate in the dark and ionize gases etc.
Refraction—When a ray of light enters from a rare medium to a denser medium, it is bent or refracted towards the normal. Mirage is formed by refraction.
Relativity theory—Theory associated with Albert Einstein based on the principle that all motions are relative and that time and space are mutually inseparable.
Rocket—A type of vehicle driven by the engine which does not depend upon air as medium. It is therefore capable of working in outer space.
‘RRR’ Bomb—The U.S. Government has begun secret exploratory research on a new nuclear ‘fast bomb’ known as RRR bomb (Reduced Residual Radiation bomb) for the military, that would produce increased heat and blast but reduced radio-active fall out.
Specific gravity—Relative weight of any kind of matter expressed by the ratio of given volume to the same volume of water (for liquid or solid matter) and of air (for gas).
Spectrum—When a narrow beam of light passes through a prism, it disperses into seven colours. The coloured image is known as spectrum.
Sterilisation—(a) Removing the power of procreation by means of operation, (b) disinfecting instruments and other materials before performing a surgical operation.
Telex—Means Teleprinter Exchange. It enables subscribers to have their own teleprinter communication direct with any other subscriber having the same facility.
T.N.T.—Tri-nitro-toluene, highly explosive substance. It is manufactured by the action of concentrated nitric acid on toluene.
Torricellian Vacuum—The vacant space above the level of mercury in the barometer is known as Torricellian Vacuum. It is so called because of its being discovered by Torricelli.
Ultra Violet Rays—The sunlight is composed of several colour such as red, orange, yellow, green, blue, indigo and violet. In the spectrum below this colour there exist other rays known as ultra violet rays. These rays possess a short wave length but high frequency.
Ultra sonic—It means frequency in excess of about 20‚000 cycles per second.
Virus—Small microscopic agents containing nucleic acid capable of multiplying in an organism and causing many types of diseases such as plague, small-pox, mumps, measles, typhus, Poliomytatin etc.
Vitamins—These are minute organic compounds present in food products and are important for maintenance of health. Deficiency of these in food causes deficiency diseases. The most important vitamins are five in number; A, B, C, D and E.
Xerography—It is a new process of graphic reproduction and photography recently developed in India by National Physical Laboratory, New Delhi.
Scientific Terms Explained
Absolute Zero—On the temperature scale is the lowest temperature theoretically possible. The theoretical point is equivalent to— 459•6ºF or—273•16º at which all molecular motion stops.
Acupuncture—It is an ancient technique, very much in vogue in China, of deadening pain. It is claimed that by the use of acupuncture major surgical operations can be performed without anaesthesia. The underlying principle is that there are several points in the body at which if needles are struck, a numbing effect is produced.
Allometry—It denotes the relationship between the growth rates of an individual plant part/or an organ/or organism.
Allotropy—Existence of a chemical element in two or more forms differing in physical properties but giving rise to identical chemical compounds.
Allelopathy—Also known as antibiosis of allelochemical interaction, which has direct or indirect inhibitory influence of one plant species or others and V/s.
Anabolism—Building up of complex substances from simple ones in living tissues. It is a part of the process of metabolism.
Anaesthetics—Drugs causing unconsciousness such as chloroform.
Antibiotics—These are the drugs which are produced by bacteria and which act against other strains of bacteria e.g. Penicillin, Streptomycin, Teramycin, Chloromycetin etc.
Astigmatism—It is an aberration of an optical system that causes lines in some directions to be focussed less sharply than lines in other directions. To the eye it causes defective vision.
Atomic Energy—It is produced due to the splitting up of atoms of certain radio-active elements. The energy produced in this manner can be used for constructive or destructive purposes.
Atomic number—The number of electrons, or what is equivalent, the positive charge on the nucleus, of an atom.
Black box—It is an apparatus which records the flight data of an aeroplane and is also a voice recorder.
Bacteria—Are minute organisms appearing under a microscopic observation as a group of rods or spheres. Some are harmful bacteria for they help in the spread of disease, some are useful for making soil fertile.
Bioeco compass—A unique device developed by Timiryazev Agricultural Academy in Moscow, which can give reliable forewarning of natural calamities like floods and droughts.
Blood group—Dr. Costello and later Dr. Moss classified blood into various groups viz. AB, A and O according to the viscosity of blood. Patients are administered blood of their own group.
Blood Transfusion—This is process of transfusing blood of one person into the blood stream of another person.
Calorie—The amount of heat needed to raise the temperature of 1 gram of water through 1ºC.
Centripetal Force—The force which tends to pull whirling objects towards the centre of rotation.
Catalyst—A substance which aids or speeds up a chemical process, without itself undergoing any change.
Chemotherapy—Treatment of diseases by means of a chemical compound having a specific bactericidal effect.
Chlorophyll—The green pigment contained in the leaves of plants. It enables the plants to manufacture food with the help of sun light. It was first discovered by P.J. Pelletier (1778-1892) and J.B. Caventon (1715-1887) in 1818.
Colour Blindness—It is an inborn condition in some people of not being able to distinguish between certain colours.
Deficiency diseases—These are the diseases which are caused due to the deficiency in the body of certain vitamins.
Dialysis—It is a machine used for blood purification when the kidneys malfunction. The process is also known as dialysis.
Dry Ice—It is solid carbon dioxide.
Efflorescence—The property possessed by certain crystalline substances of losing their water of crystallization when exposed to the air and becoming amorphous. Example—washing soda.
Electric Motor—It is a device to transform electrical energy into mechanical energy.
Electrolysis—It is the passage of an electric current through an electrolyte with subsequent migration of ions to the electrodes.
Ecology—It is the study of the balance of nature, how different living beings and inanimate objects function together as a harmonious whole.
Endemic—A disease which becomes prevalent in a particular area on account of its sorrounding conditions.
Enzymes—These are organic catalysts which actually accelerate the chemical reactions occurring in the living organism. For example lipase accelerates the hydrolysis of fats; diastase helps the conversion of starch to glucose; zymase quickens fermentation of sugar to alcohol.
Epidemic—A disease which attacks many people in a particular area at one time.
Escape Velocity—It is the minimum speed which a space craft must have to escape the earth’s “Gravitational Pull”. It is 11•2 km/sec. from the earth.
Exbiology—The new science which deals with life or possibilities of life existing beyond the earth i.e. on other planets.
Fossils—The remains or forms of a plant or animal which are found deposited at a particular place over a long period of time in the form of rocks.
Flyash—A waste product from thermal power stations using coal. The strategic metal., germanium can be extracted from flyash.
Fungi—A class of plants which have no chlorophyll.
Gene—An elementary unit of heredity. It occurs along the length of the chromosomes which surround the nuclei.
Genetic Code—The code of life by which inherited characteristics are handed down from one generation to another. The code bearing material is…D.N.A. (deoxyribonucleic acid) a biological matter which makes transmission of characteristics possible.
Green House (Glass House)—Heating influence by solar radiation reaching ground surface, allowed by CO2, ozone, dust, water, vapours, atmosphere etc.
Haemoglobin—The red pigment present in the blood functioning as an oxygen carrier.
Hibernation—Condition of sleep during certain parts of the year.
Hormones—These are chemical substances produced by ductless or endocrine glands.
Heavy water—The usual chemical formula for water is H2O.
This signifies that two atoms of hydrogen are linked with one atom of oxygen to form one molecule of water. The formula for heavy water is D2O.
Hydrophobia—It is usually caused by the bite of a mad dog. It is an incurable disease. Once it develops, the patient dies of it. It can be prevented by injections discovered by Pasteur. Injections are known as ARV (Anti-rabic venom).
Hydroponics—It is the process of growing plants by feeding them on nutrients without using soil.
Implosion—It is a technique for detonating underground nuclear devices.
Ionisation—It is the process of splitting up of a molecule into ions.
Iron Lung—A mechanical device consisting of a chamber in which alternate pulsations of high and low pressure of the thorax of a patient produce normal lung movements. It is used in cases in which respiration muscles are paralysed, e.g. in poliomylitis.
Isotopes—Atoms of the same element with the same atomic number but with different atomic mass number are known as Isotopes of that element. They contain different number of neutrons.
Kinetic energy—It is the energy possessed by the body by virtue of its motion.
Laser Beam—‘Laser’ is the abbreviated form of ‘Light, Amplification, by Stimulated Emission of Radiation’. It is a device for producing concentrated, powerful monochromatic and coherent beam of light. It is used in medicine, warfare etc.
Light Year—An astronomical measure of distance; the distance travelled by light in vacuum in one year. The velocity of light is, 3 x 108 m/s (1 light year = 9•46 x 1015 m)
Meson—A new particle which holds the protons and neutrons of the atomic nucleus discovered by a Japanese scientistYukawa.
Metabolism—It is a chemical process concerned with the burning and regeneration of tissues occurring in living organisms.
Myopia—Short-sightedness. A myopic man cannot see distant objects clearly while he can see near objects quite clearly.
Nitrogen Fixation—Nitrogen has the property of reacting under special conditions to form a number of useful products. Owing to this property the free atmospheric nitrogen is converted into so many nitrogenous compounds.
Neutralization—Addition of acid to alkali or vice-versa, so that the solution is neutralized, the properties of the compounds disappear.
Neutron Bomb—Developed by the United States, the bomb causes negligible damage to buildings and other installations, but kills people instantly through radiation.
Nuclear Fission—It is the process of breaking apart of the nucleus of an atom.
Nuclear Fuel—It is a substance which undergoes nuclear fission in a nuclear reactor.
Osmosis—In the process of a solution being separated from its pure solvent by a semi-porous membrane, the molecules of the solvent begin to travel across the membrane and reach the solution to dilute it. The process goes on till concentration is equal on both sides of the membrane. This phenomenon is known as Osmosis.
Outer space—The part of the universe which lies beyond the earth’s atmosphere where the density of matter is very low.
Oxidation—It is a process of addition of oxygen.
Photosynthesis—It is the process by which green plants manufacture food in the form of carbohydrates in the presence of sunlight.
Polymerization—Chemical union of two or more molecules of the same compound to form larger molecules. The process results in the formation of a new compound of the same empirical formula but greater molecular weight.
Potential energy—It is the energy possessed by the body by virtue of its position or shape.
Protoplasm—It is the living matter present in the cells of animal and vegetable life.
Psychedelic drugs—These are the drugs which produce a mental state of great calm.
Radiation—The process of transmission of heat in straight lines without heating the intervening medium.
Radio activity—It is a characteristic of substances like uranium, thorium, radium and actinium to emit radiation which can penetrate opaque substances, affect a photographic plate in the dark and ionize gases etc.
Refraction—When a ray of light enters from a rare medium to a denser medium, it is bent or refracted towards the normal. Mirage is formed by refraction.
Relativity theory—Theory associated with Albert Einstein based on the principle that all motions are relative and that time and space are mutually inseparable.
Rocket—A type of vehicle driven by the engine which does not depend upon air as medium. It is therefore capable of working in outer space.
‘RRR’ Bomb—The U.S. Government has begun secret exploratory research on a new nuclear ‘fast bomb’ known as RRR bomb (Reduced Residual Radiation bomb) for the military, that would produce increased heat and blast but reduced radio-active fall out.
Specific gravity—Relative weight of any kind of matter expressed by the ratio of given volume to the same volume of water (for liquid or solid matter) and of air (for gas).
Spectrum—When a narrow beam of light passes through a prism, it disperses into seven colours. The coloured image is known as spectrum.
Sterilisation—(a) Removing the power of procreation by means of operation, (b) disinfecting instruments and other materials before performing a surgical operation.
Telex—Means Teleprinter Exchange. It enables subscribers to have their own teleprinter communication direct with any other subscriber having the same facility.
T.N.T.—Tri-nitro-toluene, highly explosive substance. It is manufactured by the action of concentrated nitric acid on toluene.
Torricellian Vacuum—The vacant space above the level of mercury in the barometer is known as Torricellian Vacuum. It is so called because of its being discovered by Torricelli.
Ultra Violet Rays—The sunlight is composed of several colour such as red, orange, yellow, green, blue, indigo and violet. In the spectrum below this colour there exist other rays known as ultra violet rays. These rays possess a short wave length but high frequency.
Ultra sonic—It means frequency in excess of about 20‚000 cycles per second.
Virus—Small microscopic agents containing nucleic acid capable of multiplying in an organism and causing many types of diseases such as plague, small-pox, mumps, measles, typhus, Poliomytatin etc.
Vitamins—These are minute organic compounds present in food products and are important for maintenance of health. Deficiency of these in food causes deficiency diseases. The most important vitamins are five in number; A, B, C, D and E.
Xerography—It is a new process of graphic reproduction and photography recently developed in India by National Physical Laboratory, New Delhi.
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