DOWNLOAD HERE GENERAL SCIENCE EKOOK 2020 BY KASHMIR STUDENT
Major Parts:-
1. Physics
2. Chemistry
3. Biology
PHYSICS
In Physics, we study about a large number of physical quantities, which can be broadly classified into two categories : scalars and vectors. Scalar Quantities Physical quantities which have magnitude only. e.g. Mass, speed, volume, work, time, power, energy, etc. are scalar quantities. Vector Quantities Physical quantities, which have magnitude and direction both, e.g., Displacement, velocity, acceleration, force, momentum, torque, etc. For a quantity to be a vector, it is necessary that it follows the triangle rule of addition of two vectors.
NEWTON’S LAWS OF MOTION
First Law
Every body maintains its initial state of rest or uniform motion on a straight line unless any external force acts on it. It is also called Galileo’s law of inertia.
Example While jumping from a slowly moving train/bus one must run for a short distance, in the direction of motion.
Second Law
The force acting on an object is directly proportional to the product of the mass of the object and the acceleration produced on it.
Third Law
To every action, there is an equal and opposite reaction.
Example Bogies of the trains are provided with buffers to avoid severe jerks during shunting of trains.
Rocket moves up due to reaction of downward ejection of gas.
CIRCULAR MOTION
When an object moves along a circular path, its motion is called circular motion.
The direction of motion at any point in circular motion is given by the tangent to the circle at that point.
The external force required to act radially inward over the circular motion of the body is called centripetal force.
In the death well, the walls of well exert an inward force over the motorcycle and as a reaction, the motorcycle exert an outward force on the walls of the well.
Centrifugal force is such a pseudo force that is equal and opposite to centripetal force.
Cream separator, centrifugal dryer work on the principle of centrifugal force.
FRICTION
It is the opposing force that is set-up between the surfaces of contact of two bodies when one body slides or rolls or tends to do so on the surface of another body.
Due to friction we are able to move on the surface of Earth.
On applying brakes in automobiles, it stops only due to friction.
GRAVITATION
Everybody in the universe attracts other body by a force called force of gravitation.
The gravitational force of the earth is called gravity.
The acceleration produced in a body due to force of gravity is called acceleration due to gravity (g) and its value is 9.8m/s^2.(metre per second square)
Acceleration due to gravity is independent of shape, size and mass of the body.
Escape velocity is the minimum velocity with which an object just crosses the Earth’s gravitational field and never returns. Escape velocity at the Earth’s surface is 11.2 km/s.
Escape velocity at the Moon’s surface is 2.4 km/s. Due to low escape velocity there is no atmosphere on the Moon.
Geo-stationary satellite is used to telecast TV programmes from one part of the world to another, in weather forecasting, in predictions of floods and droughts.
Polar satellite revolves around the Earth inpolar orbit at a height of 800 km (approx). Time period of these satellites is 84 min.
These are used for weather forecasting, mapping, etc.
Pascal’s Law of Pressure
If gravitational attraction is negligible in equilibrium condition, (approx) pressure is same at all points in a liquid.
The pressure exerted anywhere at a point of confined liquid is transmitted equally undiminished in all directions throughout the liquid.
Hydraulic lift, hydraulic press and hydraulic brakes are based on the Pascal’s law of pressure.
Archimedes’ Principle
When a body is immersed partly or wholly in a liquid, there is an apparent loss in the weight of the body, which is equal to the weight of liquid displaced by the body.
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CHEMISTRY
Chemistry, a branch of physical science, is the study of the composition, properties and behaviour of matter.
Physical and Chemical Changes
Physical changes are the changes which only affect the physical properties like colour, hardness, density, melting point etc, of matter, but do not affect the composition and chemical properties of matter.
A physical change is temporary, while a chemical change is permanent.
Crystallisation, sublimation, boiling, melting, vaporisation, cutting of trees, dissolving sugar or salt in water etc are physical changes.
Chemical changes affect the composition as well as chemical properties of matter and result in the formation of a new substance.
Burning of fuel, burning of candle and paper, electrolysis of water, photosynthesis, ripening of fruits etc, are examples of chemical changes.
MATTER
Anything which occupies space and has mass is called matter. In general, it exists in three states i.e., solid, liquid and gas.
Now-a-days there is a discussion on two more states of matter i.e., Plasma (Ionised gases containing super energetic and super excited particles) and Bose-Einstein Condensates or BEC (a gas at super low temperature with extremely low density).
Boiling Point
The temperature at which liquid converts into vapour is called its boiling point.
Boiling point of water is 100°C.
The boiling point increases in the presence of impurities that’s why boiling point of sea water is more than the boiling point of pure water (as the former contains impurity).
It usually decreases at high altitudes. That’s why at high altitudes, the boiling point of water is less than 100°C and more time is required to cook a food.
Melting Point
It is a temperature at which a substance converts from its solid state to liquid state. Melting point of ice is 0°C. It decrease in the presence of impurity.
ATOM, MOLECULE AND ELEMENT
An atom is the smallest particle of the element that can exist independently and retain all its chemical properties.
Atom is made up of electrons, protons and neutrons.
Protons and neutrons reside in the nucleus (at the centre of atom) whereas electrons revolve around the nucleus.
A molecule is the smallest part of an element or a compound cabable of independent existence under ordinary conditions.
Element contains only one type of atoms. e.g. carbon (C), sulphur (S), diamond, graphite etc.
Ununseptium (a superheavy chemical element with atomic number 117) is a member of group-17 in the periodic table below the five halogens (fluorine, chlorine, bromine, iodine and astatine). Its synthesis was claimed in Dubna, Russia by a joint Russian-American collaboration.
In 2014, the GSI Helmholtz Centre for Heavy Ion Research in Germany also claimed to have successfully repeated original experiment.
Dating Techniques
Radiocarbon dating is used to determine the age of carbon bearing materials like wood, animal fossils etc.
Uranium dating is used to determine the age of Earth, minerals and rocks.
Colloids
These are heterogeneous solutions, containing two phases : dispersed phase and dispersion medium.
These show Tyndall effect (i.e. scattering of light by colloidal particles) and Brownian motion (zig-zag motion).
Colloids can be dispersion medium loving (i.e. lyophilic) or dispersion medium repelling (i.e. lyophobic).
Battery
Battery is a device, used to convert chemical energy into electrical energy and is of two types :
Primary batteries (non-rechargeable) act as galvanic cell, e.g. dry cell, mercury cell etc.
Secondary batteries (rechargeable) act as galvanic as well as voltaic cell e.g. lead storage battery, nickel cadmium battery etc.
In electrolytic refining, anode is made by impure metal and a strip of pure metal acts as cathode.
Fire Extinguishers
Water extinguishes fire because as it evaporates the vapours surround the burning substance, cutting off the oxygen supply, thus inhibiting burning process.
In case of electrical or oil (petrol) fires, water cannot be used as extinguisher. This is because water is a conductor of electricity and heavier than oil. Thus, oil floats over it and continues to burn. Carbon dioxide, which is generated by the reaction of baking soda with acid, is used to extinguish electrical or oil fires.
Quality of petrol is measured in terms of octane number and that of diesel in terms of cetane number. TEL (Tetra Ethyl Lead) is an antiknock compound. Higher the octane number better is the quality of fuel.
Fuels
The substance, which produce heat and light on combustion are called fuels.
A strong foul smelling substance, called ethyl mercaptan, C2H5SH, is added to LPG to detect its leakage as LPG is an odourless gas.
The amount of heat obtained, when 1g of a fuel is burned in excess of oxygen is called calorific value.
Vehicle carrying inflammable substances have metallic ropes, touching the ground during motion in order to provide earthing for lightning.
Fuels used in rocket are called rocket
propellants. A mixture of liquid hydrogen and liquid oxygen, is most common rocket propellant.
Safety Matches
In safety matches, the stick consists of a mixture of antimony trisulphide and potassium chlorate at its one end. The box side contains a mixture of powdered glass and red phosphorus.
ACIDS, BASES AND SALTS
Acids
These are the substance, which have a sour taste and turn blue litmus red.
These are good conductor of electricity in aqueous solution.
Pickels are always kept in glass jar because acid present in them reacts with metal to produce hydrogen gas.
Bases
These are the substances, which have bitter taste, soapy to touch and turn red litmus blue.
Bases like NaOH, KOH, etc. are good conductors of electricity in their aqueous solution and in molten state.
Base react with acid to form salt and water.
Salts
These are the product of neutralisation reaction between an acid and a base.
pH is the measure of acidity/basicity.
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BIOLOGY
Biology (coined by Lamarck and Treviranus 1802), is a branch of science which deals with study of living organisms. It mainly includes Botany (Study of plants) and Zoology (Study of animals). The scientist who gave this thoughts for the first time about the life of plants and animals was Aristotle, that’s why he is known as the father of Biology. He is also known as the father of Zoology.
LIVING WORLD
- In 18th Century, Carolus Linnaeus developed binomial nomenclature for living organisms, i.e., scientific name consisting of genus and species.
- Whittaker (1969) classified living organisms into five kingdoms—Monera, Protista, Fungi, Plantae and Animalia.
- Monera includes bacteria and Mycoplasma, while Protista includes Protozoa (unicellular Eukaryotes).
- Viruses are sub-microscopic, obligate, intracellular parasite consisting of nucleoprotein.
- WM Stanley firstly crystallised TMV (Tobacco Mosaic Virus).
- Viroids are smallest infectious single stranded RNA molecules discovered by TO Diener.
THE CELL
According to cell theory proposed by Schleiden and Schwann (1838) cell is the structural and functional unit of living organisms.
An organism may be composed of single cell (unicellular) or many cells (multicellular).
Cells are of two types i.e., prokaryotic (which lacks nucleus and membrane bound organelles) and eukaryotic (which have nucleus and membrane bound organelles).
Prokaryotic cell is found in bacteria, mycoplasma and blue-green algae while eukaryotic cell in plants, animals and fungi.
Nucleic Acids
These contain the genetic instructions used in the development and functioning of all known living organisms. These are of two types namely DNA and RNA.
Deoxyribo Nucleic Acid (DNA) It is a long polymer made from repeating units called nucleotides. It has four bases i.e. adenine, guanine, cytosine and thymine.
Ribo Nucleic Acid (RNA) It is also made up of a long chain of nucleotides. It contains uracil in place of thymine.
HUMAN SYSTEMS
The cells of human and other multicellular animals are organised into tissues. Two or more tissues grouped together to form organs. An organ system is a group of organs that function together to carry out the principal activities of the body.
Digestion Digestion is the process by which complex food is converted into simple components with the help of digestive enzymes, i.e. hydrolysis process.
Respiratory System
Respiration in an oxidative process involving oxidation of food substances such as carbohydrate, fat and proteins to form CO2.
Respiration may be anaerobic, (i.e. without O2, water and to release energy. ) and aerobic (i.e. withO2).
Blood (Lymphatic System)
Fluid connective tissue composed of plasma and blood cells.
An adult person has 5-6 litre blood.
It is slightly alkaline having pH 7.3-7.4.
Plasma is pale yellow transparent and constitute about 60% volume of blood.
Plasma is composed of 90-92% water, 7% organic substances (albumin, globulin and fibrinogen protein) and 1% inorganic substances.
Red blood corpuscles (Most abundant) are non-nucleated and contains haemoglobin (the respiratory pigment).
White blood cells are colourless, nucleated and granular or agranular.
Eosinophils are also called acidophils. (2-8%) are phagocytic granulocytes and play important role in hypersensitivity.
Basophils (2%) are non-phagocytic granulocytes and increases during chickenpox.
Neutrophils (65%) are phagocytic granulocytes and increase during bacterial infection.
Monocytes (0.5%) are agranulocytes called policeman of blood and increase during tuberculosis.
Lymphocytes (26%) are agranulocytes producing antibodies and increase during viral infection.
Platelets(thrombocytes) are non-nucleated. Platelets have a life span of about 8 to 10 days.
Rh factor discovered by Landsteiner and Veiner in Rhesus monkey, which is responsible for erythroblastosis foetalis disease.
Important component of blood clotting are fibrinogen, prothrombin, thromboplastin, calcium ions and Vitamin-K.
Heart
Human heart is myogenic i.e., contraction is initiated by a pulse produced by SinuAtrial node (SA node) located in right atrium. It is also called pacemaker. First heart sound is lub and second heart sound is dub.
Contraction of heart is called systole. 120 mm Hg, while relaxation is called diastole (80 mm Hg).
Excretion
It is the process elimination of harmful waste products from the animal body to regulate the composition of the body fluids and tissues.
Human excretory system is composed of two kidneys. Nephron is the structural and functional unit of kidneys.
Colour of urine is pale yellow. It is due to pigment urochrome.
Human urine contains about 95%water, 2% salts, 2.6% urea and 0.3% uric acid.
Ebola Virus
According to World Health Organisation WHO’s 19th August, 2015 Situation Report, there were three confirmed cases of Ebola reported in the week up to 16th August all of which were reported from Guinea. For the first time since the beginning of the outbreak in Sierra Leone, a full epidemiological week has passed with no confirmed cases reported. A total of 72 cases remain under monitoring in Sierra Leone. On 29th, June 2015, a confirmed case of Ebola was reported in a 17 year old male who had died in Liberia. Apart from Africa, ebola virus has spread to USA, Spain, Mali and to an extent in Italy and UK.
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