1. Artery & Vein

Artery

i) Arteries are blood vessels which transport blood away from the heart.
ii) Arteries have thick vascular walls.
iii) The inside bore or lumen of arteries is narrow.
iv) Arteries carry oxygenated blood with the exception of pulmonary artery.
v) The walls of arteries are more elastic.
vi) The blood is under great pressure in the arteries.
vii) Arteries are generally deeply placed.
viii) Arteries end in the capillaries.
Vein:

i) Veins are the blood vessels which always carry blood towards heart.
ii) Veins have thin muscular walls.
iii) The inside bore or lumen of veins is wide.
iv) Veins carry deoxygenated blood with the exception of pulmonary veins.
v) The walls of veins are less elastic.
vi) The blood is under less pressure in the veins.
vii) Veins are generally superficially placed.
viii) Veins start from the capillaries.

2. PNP and NPN Transistor

1. NPN has higher electron mobility than PNP. Therefore, NPN bipolar transistors are often more
favoured than PNP transistors.
2. NPN is easier to create from silicon than PNP.
3. The main difference of NPN and PNP is the base. One is just the opposite of the other.
4. With the NPN, a P-dope semiconductor is the base, while with the PNP, the ‗base‘ is a N-dope
semiconductor.

3. Electronic & Static Electricity

Electronic Electricity

i) This is electricity in motion.
ii) It involves flow of electrons.
iii) It has high voltage.

Static Electricity:

i) This is electricity at rest.
ii) It does not involve flow of electrons.
iii) It has low voltage.
4. Concave & Convex Lens

Concave Lens

i) It is the lens which is narrower in the centre and broader towards the corners.
ii) When a beam of light strikes a concave lens all the rays after passing through it diverge.
iii) It gives mostly virtual image.
iv) They are also called diverging lenses.

Convex Lens:

i) It is the lens which is narrower towards the corners and broader towards the centre.
ii) When a beam of light strikes a convex lens all the rays after passing through it converge at a single
point.
iii) Mostly real images are formed except when the ray of light passes through it when object is
palced between optical centre and focus.
iv) They are also called converging lenses.

5. Absorption & Adsorption

Absorption

i) Absorption is a process in which a substance takes up another substance, such as blotting paper (solid) absorbing water (a liquid). OR Adsorption and absorption are two different things. Absorption is the chemical integration of one chemical into another. When you drink a glass of water, you are
absorbing it, as the water becomes part of you.

Adsorption:

i) Adsorption is a process in which a substance adheres to the surface of another substance.

Adsorption is important in some types of catalysis, notably where gases adsorb on metal surfaces.

The reaction is then made easier by a consequent lowering of activation energy. OR Adsorption occurs when one substance holds another via physical bonds. If you spill a glass of water on your shirt, it is adsorbed as the fibres will hold the water until heat dries out the shirt.

6. Fats & Oils

Fats


i) are solid at room temperature
ii) made by animals, mostly
iii) are more saturated

Oils:

i) are liquid at room temperature
ii) are made by plants, mostly
iii) are less saturated

Hypoglycaemia:

i) The fall in sugar level in the blood below the normal physiologic level known as Hypoglycaemia.

Normal physiologic range of sugar in blood is 60-90mg% at fasting and 120-140 mg% at random.
ii) It is treated by giving intravenous glucose.
iii) It causes mental confusion, visual problem and often coma etc.
iv) It causes weakness and increases in food desire.

Hyperglycaemia:

i) Hyperglycaemia is a condition in which blood sugar level rise above its normal range.
ii) It is treated by exercise, medicine or by intravenous insulin therapy.
iii) It causes weakness, calf pain, unhealed wounds and kidney problem.
iv) It causes excessive urination, dryness of lips and increased thirst etc

2. Epidemic & Endemic

Epidemic:

i) If at one place and times a great number of people suffer from a disease is known as epidemic.
ii) It can travel from one place to another.
iii) Examples: Influenza, Smallpox, Cholera etc.

Endemic:

i) If a disease persists in a particular locality, certain area or one region, it is known as endemic
disease.
ii) It cannot travel from one place to another place.
iii) Example: Goitre in iodine deficient areas.

3. Herbivores & Carnivores


Herbivores

i) The animals eating green plants, grass and fodder are known as Herbivores.
ii) Animals have specific digestive system to digest leaves, plants and fodder.
iii) The teeth are specifically designed to cut and chew leaves, plants and fodder.
iv) Jaw movement is specific for side motion.
v) Examples: goats, cattle, sheep, buffalo, cow etc.

Carnivores:

i) The animals eating flesh and meat are known as carnivores.
ii) Digestive enzymes are specific.
iii) Their teeth are short and to cut and chew leaves, plants pointed especially for flesh eating.
iv) Jaw movement is specific for up and down movement.
v) Examples: Tiger, dog, cat, lion etc.

4. Respiration & Photosynthesis

Respiration

i) Respiration is a catabolic process in which compounds are broken down.
ii) In this process carbohydrates are broken down into simpler compounds.
iii) The end-products for this process are CO2 and H2O.
iv) In respiration Oxygen enters the plant body and CO2 is released.
v) It occurs during both day and night. Light is not necessary for this process.
vi) In respiration energy is released from food material.

Photosynthesis

i) It is an anabolic process in which compounds are formed.
ii) In this process carbohydrates are manufactured.
iii) The end-product of this process is simple carbohydrates.
iv) In photosynthesis CO2 enters the plant and O2 is released.
v) It occurs during day time only. Light is essential for this process.
vi) It is energy consuming process.

5. Pollination & Fertilization

Pollination

i) It is a process involving transfer of pollens form male reproductive organ to female reproductive
organ of plants.
ii) It occurs in flowering plants.
iii) The products of pollination are seed.
iv) It takes place through animals, birds, insects, wind and water.

Fertilization:

i) In fertilization fusion of egg and sperm occurs.
ii) It occurs markedly in animals.
iii) The product of fertilization is zygote.
iv) It takes place by physical contact and mating of male and female.

Thermoplastics

i) Plastics that can be melted again and again are known as thermoplastics.
ii) They behave just like wax.
iii) These plastics can be shaped again and again.
iv) Examples: Nylon, PVC, Teflon etc.
Thermosetting Plastics:
i) Plastics that can be melted only once are known as thermosetting plastics.
ii) They become hard after melting.
iii) These plastics cannot be shaped again and again.
iv) Examples: Polyesters and Bakelite.

Lunar & Solar Eclipse

Lunar Eclipse

i) It occurs when the earth comes between moon and sun.
ii) Moon goes through series of partial eclipses when moon comes out of umbral region of earth‘s
shadow.
iii) Earth lies in umbral region at total eclipse when earth lies exactly between moon and sun and its
shadow covers the whole moon.

Solar Eclipse

i) It occurs when moon comes between earth and sun.
ii) Partial eclipse of sun occurs as in Penumbra can see a part of the sun.
iii) At the total eclipse of the sun, the shadow of moon which it throws on earth consists of an umbra
and penumbra people on earth who are in umbral region cannot see the sun.

Asteroid & Meteorite

Asteroid:

i) The small rocky objects which are orbiting the sun between orbits of Mars and Jupiter are known
as asteroids.

ii) Its origin is concentrated to the remains of planets that fell apart.
iii) Asteroid means star like but these are known as minor planets.

Meteorite:

i) Tiny chunk of material floating in space, which can also enter the earth‘s atmosphere and become
meteor are known as meteorites.
ii) It may originate by the disintegration of comet.
iii) A falling star (Meteor) is seen as a streak of light in sky.

Renewable & Non-renewable resources

Renewable Resources

i) Renewable resources are used continuously and can be used again and again.
original materials, causing the reactant's stored energy to decrease. (In scientific terms, the reactants
have "less total enthalpy" than the product.)
iii) The resulting product of the reaction is less stable because, the higher the energy bond, the less
strength its molecules possess.
iv) Most endothermic reactions are not spontaneous.
v) Example: Melting ice. In order for ice to melt, it needs to draw in the heat (energy) from its
surroundings. The ice becomes less stable as it responds to the increased heat. The ice stored energy
decreases. The end product
ii) Major examples are: air, water, soil, wildlife, forests, fish etc.
iii) These resources support millions of people all over the world.
iv) Renewable resources are constantly renewed by bio-geochemical cycles of nature.

Non-renewable Resources

i) Non-renewable resources cannot be used again and again after their consumption.
ii) Major examples include: Coal, oil, natural gas etc.
iii) These resources cannot support millions of people all over the world.
iv) Non-renewable resources are being exhausted day by day because their demand rises. Due to
worldwide demand of fossil fuels, its supplies are declining.
OR

Renewable resources-

1) the resources that can be renewed by reproduction are called renewable resources.
2) Renewable resources are inexhaustible.
3) Renewable resources are not affected by the human activities.
4) All biotic resources are renewable.
5) For example: air and water.


Non-renewable resources-

1) the resources that are present in fixed quantities are called non-renewable resources.
2) Non-renewable resources are inexhaustible.
3) Non-renewable resources are affected by human activities.
4) Some abiotic resources are non-renewable.
5) For example- fossil fuels and minerals.

__________________
God has sent us to do something special,Life is once for all but not to be Repeated by a pendulum.

Endothermic & Exothermic Reaction

Exothermic Reaction

i) Energy is drawn in from the external environment, causing its surroundings to loose heat, or "cool down."
ii) The endothermic chemical reaction creates a product that has a higher energy level than the original materials, causing the reactant's stored energy to decrease. (In scientific terms, the reactants have "less total enthalpy" than the product.)
iii) The resulting product of the reaction is less stable because, the higher the energy bond, the less strength its molecules possess.
iv) Most endothermic reactions are not spontaneous.
v) Example: Melting ice. In order for ice to melt, it needs to draw in the heat (energy) from its surroundings. The ice becomes less stable as it responds to the increased heat. The ice stored energy decreases. The end product is water, which has a higher energy level than the ice.

Exothermic Reactions

i) Exothermic chemical reactions cause their surroundings to warm up by giving off heat.
ii) The reactants contain more stored energy than the product because energy from external sources is not required, but given off. This gives the product more stability due to the lower amount of energy needed. (In this case, the reactants have a "greater total enthalpy" than the product.)
iii) Exothermic reactions are usually spontaneous.
iv) Example lighting a match. When the head of the match is struck, it results in the spontaneous release of stored energy (heat) from the reactants into the surroundings. The flame that is produced has a lower level of energy than the match and the striking surface because the reaction is giving off
stored energy and not required to draw energy in from its surroundings.

Star & Planet

Star

i) Stars are self-luminous heavenly bodies.
ii) They do not revolve around the sun.
iii) They are usually stationary.
iv) Examples: fixed stars, binary stars.

Planet:

i) Planets are rocky non-luminous bodies.
ii) They revolve round the sun.
iii) They usually move.
iv) Examples: Mercury, Venus, Jupiter etc.

Nuclear Fission & Fusion

Fission:

i) Lighter atoms are fused together at a very high temperature to form heavier elements.
ii) It is difficult to carry out on the earth.
iii) It has no nuclear waste problem.
iv) It requires cheaper and abundant elements.
v) Not possible at concerning scale as high temperature is needed to start it.

Fusion:

i) Heavier unstable atoms are broken down to produce energy.
ii) It is easy to carry out on the earth.
iii) It has nuclear waste radioactivity disposal problem.
iv) It requires expensive and rare elements.
v) Possible to commercialize under controlled measure.

RAM

i) It stands for random access memory.
ii) It is an optical disc, where data and information is stored permanently.
iii) RAM is the primary storage media.
iv) RAM is the primary storage device from which the system boots.
v) RAM is stored on RAM chip.
vi) The data or information stored on it can be written on or it can be erased.

ROM

i) It stands for read only memory.
ii) It is that part of CPU, where temporary information is stored.
iii) RIOM is the secondary storage media.
iv) System does not boot from ROM.
v) ROM is stored on a compact disc.
vi) The data or information stored on it neither be written on, nor it can be erased.

BIT & BYTE

A bit is defined as: a single basic unit of information, used in connection with computers and electronic communication. All modern computers store and use data in digital form. The smallest unitof storage and measurement is one binary digit, therefore its name.A byte, pronounced ‗bite‘, is the next size up basic unit of measurement for information storage,usually consisting of eight bits. These 8 bits are grouped together to form a byte that is, a total or 8grouped bits representing one character of data.Therefore, so far we have two basic units of measuring digital information storage that have different capacities, they are:
• 1 Bit
• 8 Bits equal 1 Byte

CU & ALU

CU

i) It stands for Control Unit.
ii) Control unit controls overall activates of computer.
iii) CU does not perform the functions of calculations.

ALU

i) It stands for arithmetic logic unit.
ii) It performs arithmetic and logical operations.
iii) ALU performs functions of addition, subtraction, multiplication and division.
Hardware & Software

Hardware:
i) All the physical components of computer which can be touched, measured have weight and occupy
space are collectively called computer hardware etc.
ii) Examples of hardware are: keyboard, mouse, joy stick, scanner, printer, CPU etc.


Software:

i) Software can be defined as a set of instructions and codes written in a defined manner. In other words software are pre-written programs, which control the operation of computer.
ii) Examples of software are; DOS, windows, UNIX, XENIX, Linus, JAVA, Oracle, Antivirus etc.
PC/Minicomputers & Mainframe computers
PC:
i) It is a small computer based on microprocessor.
ii) One user can use it at a time.
iii) These are very low priced computers. An individual can afford it.
iv) User friendly software are used to operate this computer.
v) Minicomputers were launched in 1959 by Digital Equipment Corporation (DEC)
vi) Minicomputers are also made by Data General, Hewlett-Packard & IBM

Mainframe Computers:

i) The largest computers called mainframe computers are the oldest category of computer system.
ii) They are capable of great processing speed and data storage.
iii) These are always kept in air-cooled rooms.
iv) They are mainly used in banks, airlines and industrial companies.

Email & Snail Mail

Snail mail


i) "Snail mail" is a term used to refer to mail that is sent in the traditional way — through the postal service — rather than by email, fax, or other electronic means of communication.
ii) It is called "snail mail" because it can be very slow, as is a snail. Snail mail generally takes 2 or 3 days to go from origin to destination, if not many more,
iii) Snail mail has gone out of fashion for simple letters, though it is still necessary for sending packages, or legal documents that require signatures.

Email:

i) Email is electronic mail which is very quick means of communication through computers and telephone line.
ii) Email can be sent instantly.
iii) With email, a message is sent directly from a user's mail program to another person's email address. Though many email messages simply contain words, they may also include photos or other digital files, such as songs, or links to websites

__________________
God has sent us to do something special,Life is once for all but not to be Repeated by a pendulum.

Apes & Monkeys

Apes:

i) Apes do not have tail.
ii) Apes have rounded nasal openings.
iii) Apes generally have bigger brains and larger bodies than monkeys.
iv) Apes do not have web foot.
v) Apes are bigger in size.
vi) Apes are: Humans, Chimps, Gorillas, Orangutans and Gibbons.

Monkeys

i) Monkeys have tails.
ii) Monkeys have slanted nasal openings.
iii) Monkeys have web foot.
iv) Monkeys are smaller in terms of size
v) Monkeys are all primates non-apes and non-prosimians (lemurs)

Hydrostatics & Hydrodynamics

Hydrostatics:

i) Hydrostatics is a branch of science which deals with physical behaviour of liquids at rest.
ii) The consideration of liquids at rest, involves problems of buoyancy and flotation, pressure on dams and submerged devices, and hydraulic presses.


Hydrodynamics:

i) Hydrodynamics is the branch of science which deals with behaviour of liquids in motion.
ii) The study of liquids in motion is concerned with such matters as friction and turbulence generated in pipes by flowing liquids, the flow of water over weirs and through nozzles, and the use of hydraulic pressure in machinery.

Comet & Meteor

Comet:

i) Comet is a collection of gas, dust, and volatile ice that travel around the sun, generally in very eccentric orbit.

Meteor:

i) Meteor is a streak of light seen in the night sky signify the burning up in earth‘s atmosphere of inter-planetary material.

Barrage & Dam

Barrage:

i) Barrages are constructed not at a much height but at a low height.
ii) Barrages are single purpose constructions i.e. for irrigation.
iii) Electricity cannot be produced in barrages.
iv) It is constructed on plains.
v) Sukkur barrage is an example.

Dam:

i) Dams are constructed at higher elevation or at a height.
ii) Dam is multipurpose. It acts as reservoir, control flood, and for irrigation.
iii) Dam is constructed to generate electricity.
iv) It is impossible at ground level.
v) Tarbella dam is an example.

Isotopes:

These are the elements having same atomic number but different mass number. They have the same atomic number because the number of protons inside their nuclei remains the same.

The difference in their mass number is due to the difference in their number of neutrons.

__________________
God has sent us to do something special,Life is once for all but not to be Repeated by a pendulum.

Isobars

Where Isotopes are chemically the same and physically different, the converse is true in Isobars. That is isobars are elements, which are chemically different but physically the same. So, isobars are atoms of different elements having the same atomic mass but different atomic number. Since their number of electrons is different, their chemical properties are different.

The light nuclei have unstable isobars. Heavy nuclei have stable isobars and these occur in pairs. Suppose the number of protons of one isobar matches with that of another they are called as mirror-nuclides of each other.

Autopsy & Biopsy

Autopsy:

i) An autopsy is the dissection and analysis of a dead subject.
ii) , autopsies are limited to the deceased and there are two kinds of autopsy; External examination and internal examination.
iii) Autopsy is performed for medico-legal purpose.

Biopsy:

i) A biopsy is a medical test in which cells, tissue, or fluid is removed for examination.
ii) Biopsy is not limited to only living people because they are routinely taken from organs that are going to be used for transplantation.
iii) Autopsy is performed for diagnosis purpose.

Mitosis & Meiosis

Mitosis:

i) Mitosis takes place within somatic cells (cells that make up the body).
ii) One single division of the mother cell results in two daughter cells.
iii) A mitotic mother cell can either be haploid or diploid.
iv) The number of chromosomes per nucleus remains the same after division.
v) It is preceded by a S-phase in which the amount of DNA is duplicated.
vi) In mitosis, there is no pairing of homologous chromosomes.
vii) There is no exchange of DNA (crossing-over) between chromosomes.
viii) The centromeres split during anaphase.
ix) The genotype of the daughter cells is identical to that of the mother cells.
x) After mitosis, each daughter cell has exactly same DNA strands.

Meiosis:

i) Meiosis takes place within gamete cells (sex cells).
ii) Two divisions of the mother cell result in four meiotic products or haploid gametes.
iii) A meiotic mother cell is always diploid.
iv) The meiotic products contain a haploid (n) number of chromosomes in contrast to the (2n) number of chromosomes in mother cell.
v) In meiosis, only meiosis I is preceded by a S-phase.
vi) During prophase I, complete pairing of all homologous chromosomes takes place.
vii) There is at least one crossing-over or DNA exchange per homologous pair of chromosomes.
viii) The centromeres do separate during anaphase II, but not during anaphase I.
ix) Meiotic products differ in their genotype from the mother cell.
x) After meiosis, each daughter cell has only half of the DNA strands.

Hard water & Heavy Water

Hard Water:

i) Hard water is that type of water which does not form lather easily.
ii) Its formula is H2O.
iii) Hard water is not used in nuclear power plants.

Heavy Water:

i) Heavy water is deuterium oxide in which hydrogen of water is replaced by its heavier

isotope, Deuterium.

ii) The formula of heavy water is D2O.
iii) Heavy water is used in nuclear power plants.

Climate & Weather

Climate:

i) Climate is the normal weather conditions for an area during a season or a year.
ii) Climate of an area is described by means of an average means of an average of the statistics of the various weather factors over a period of time, normally 30-years.

Weather:

i) Weather is the condition of the atmosphere at any one place and time.
ii) Weather is described by air, temperature and humidity, wind speed and direction, cloud amount and precipitation, sunshine and visibility.

Cardiac & Skeletal Muscles:

Cardiac Muscles:

i) Cardiac muscles are present in the heart only.
ii) They have centrally placed nuclei.
iii) They never fatigue.
iv) They are composed of long fibres.
v) They are under involuntary control.

Skeletal Muscles:

i) Skeletal muscles are present in the skeleton of the body.
ii) Nuclei are not centrally placed in skeletal muscle.
iii) They can fatigue.
iv) They are not composed of long fibres.
v) They are under voluntary control.

__________________
God has sent us to do something special,Life is once for all but not to be Repeated by a pendulum.

Haze & Smog

Haze:

i) The dust particle smoke etc. that may be visible in atmosphere close to the earth‘s surface is known as Haze.
ii) It does not affect natural visibility.
iii) It does not occur particularly near coastal areas.

Smog:

i) It is a mixture of solid and liquid fog as well as particles of smoke. It is formed whenhumidity is high.

ii) Smog reduces visibility.
iii) It occurs near coastal areas.

Enzyme & Hormone

Enzyme:

i) These are organic catalysts produced in the protoplasm of all living cells.
ii) These are mostly protein in nature.
iii) They control all biochemical reactions of the cell.
iv) These are present in all cells and show their activity there.

Hormone:

i) These are organic substances produced in places away from their functional sites.
ii) These are mostly acids.
iii) They promote and inhibit growth, flowering, sex expression, etc.
v) These are mobile. They are produced at one site and show their activities at other

__________________
God has sent us to do something special,Life is once for all but not to be Repeated by a pendulum.

Antibodies

They are what your body produces in response to the presence of antigens (bacterial or viral surface structures).
They merely assist your white blood cells in identifying
They also destroy and invade the unidentified microorganisms.


Antibiotics

They are chemicals that work to destroy invading bacteria (usually by disrupting the outer cell wall and making it "leak" or by messing up the bacteria's metabolic processes. They are not produced by the body).
Antibiotics can be antibacterial or antiviral. Antibacterial will only destroy bacteria and antiviral will only destroy viruses. There are not many antibiotics for viruses. Also a virus is not a eukaryote.

Antigen & Vaccine

Antigen:

A substance or organism that induces the production of an antibody. The antigen reacts with antibody. The antigen tissue proteins can cause problems in the transplant of organs by rejecting the introduction of new organ in the body.

An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader. These invaders can be molecules such a spollen or cells such as bacteria. The term originally came from antibody generator and was a molecule that binds specifically to an antibody, but the term now also refers to any molecule or molecular fragment that can be bound by a major his to compatibility complex (MHC) and presented to a T-cell receptor. "Self" antigens are usually tolerated by the immune system; whereas "Non-self"antigens are identified as invaders and attacked by the immune system. self-antigens
.
Vaccine:

The agent which is used to give immunity against various diseases. A vaccine consists of modifieddisease organisms such as live weakened viruses or dead that can induce the production of antibodies within the blood.A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins. The agent stimulates the body's immune system to recognize the agent as foreign, destroy it, and "remember" it, so that the immune systemcan more easily recognize and destroy any of these microorganisms that it later encounters.

Vaccines can be prophylactic (example: to prevent or ameliorate the effects of a future infection by any natural or "wild" pathogen), or the rapeutic (e.g. vaccines against cancer are also being
investigated; see cancer vaccine).

8. Short/Long Notes

Solar System

The solar system is the family of the sun, planets revolving around it, the satellites of the planets and the asteroids or meteoroids and comets etc.
• There are eight planets in the solar system.
• Starting from the sun there are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

• All the planets revolve around the sun in their orbits.
• Meteorite analysis shows that the age of solar system is about 4530 million years.
• The sun is not the largest star of the Milky Way; rather it is an average sized star.
• It is not at the centre of the galaxy but shifted towards a side.
• The diameter of the sun is 1, 392, 140 km and its mass is 2 * 1027 tonnes.
• The outermost layer of the sun is called photosphere, has an average temperature of 5570 0C.
• The photosphere rotates at a rate of 25.38 days per turn.
• At the centre of the sun hydrogen is undergoing nuclear fusion reaction which provides energy for the heat and light so sun.
• The planets of the solar system as well as the moons get light and sometimes heat from the

sun.

• The four inner planets of the solar system are called terrestrial plants because of their rocky

nature.

• The outer planets are called gaseous planets because they don‘t have solid surface and are
composed of gases.

__________________
God has sent us to do something special,Life is once for all but not to be Repeated by a pendulum.

Planets And Their Characteristics:

1. Mercury

• Its distance from Sun is 58 million kms.
• Its revolution period is 88 days.
• Its rotation period is 58 days, 15 hours and 30 minutes.
• It has no moon.
• It is the nearest planet to the sun.
• It is also the smallest planet of the solar system.
• It is the fastest planet.
• Its radius is 2,433 kms and diameter is 4,878 kms.
• It is covered with holes called Craters.
• It has no atmosphere.
• The temperature on mercury vary between 420 0C (7900F) in the day and -180 0C (-2900F) at
nights.

2. Venus

Apart from the moon, Venus is the brightest object in the sky. Venus can be seen with naked eye in the morning or in the evening. Following are the main characteristics of the Venus.

• Its distance from the Sun is 108 million kms.
• Its revolution period is 224.7/225 days.
• Its rotation period is 243 days and 14 hours (longest day)
• It has no moon.
• It is the nearest neighbour of the earth in the solar system.
• It is the brightest planet.
• It is also the hottest planet.
• Its diameter is 12,102 kms.
• It is wrapped in thick clouds of CO2 gas.
• It rotates from east to west as opposite to most other planets.

3. Earth

The earth is the largest and the densest of the four terrestrial planets. It is the most wonderful planet of the solar system. Following are the features of the Earth.

• Its distance from the Sun is 150 million kms.
• Its revolution period is 365 ¼ days.
• Its rotation period is 23 hours, 56 minutes, 40 seconds.
• It has one moon.
• It is the densest planet.
• It is also the watery and bios planet.
• Its diameter is 12756 km (7927 miles equatorial and 7900 miles polar diameter)
• It has atmosphere which contains 78% Nitrogen, and 21% Oxygen.
• Its two-thirds surface is covered with oceans.
• The earth‘s surface is rich in Oxygen, Silicon, Aluminium, Iron, Calcium, Sodium etc.

4. Mars

• Distance from sun 228 million kms.
• Revolution period 687 days.
• Rotation period 24 h, 37 min and 22 sec.
• It has two moons Phobos and Deimos.
• Its diameter is 6794 kms.
• Mars is covered with red dust.
• It has an atmosphere composed almost entirely of CO2.
• Its average temperature is -53 0C.

5. Jupiter

• Its distance from sun is 778 million kms.
• Revolution period 12 years.
• Rotation period 9h, 50min, and 30 sec. (smallest day)
• It has 63 moons.
• It is the largest planet of the solar system.
• It has the largest number of satellites.
• Its diameter is 1, 24,800 kms.
• Its diameter is eleven times greater than the earth‘s diameter.
• It has a dense, cloudy atmosphere of hydrogen and helium.
• It has a rock-iron-ice core about 15, 000 km (9,000 miles) thick.
• Jupiter radiates 67% more heat than it receives from the sun. this is mainly due to dissipation of the primordial heat of the planet.

6. Saturn

In 1610, Galileo became the first person to look at Saturn through telescope.
• Distance from Sun 1427 million kms.
• Revolution period 30 years.
• Rotation period 10h, 14 mins.
• It has 62 moons.
• The largest moon of Saturn is the Titan and it is the second-largest moon in the solar system. Titan is larger than the planet Mercury.
• It is the second largest planet.
• It has a magnificent system of rings.• Its diameter is 1, 20, 000 km.

7. Uranus

When sky is very dark and very clear Uranus can be seen with the naked eyes. The planet was discovered by William Herschel in March 1787.
• Its distance from Sun is 2869.9 million kms.
• Revolution period is 84 years.
• Rotation period is 16h, and 10 mins.
• It has 27 moons.
• Titania is the largest moon of Uranus.
• It has an atmosphere which is dominated by hydrogen and helium.
• Its diameter is 52, 400 km.

8. Neptune

Neptune was discovered by the German astronomer Johann Galle.
• Distance from Sun 4496, 6 million kms.
• Revolution period 165 years (largest year)
• Rotation period 18 hours.
• Neptune has 13 moons that we know of. The largest moon is Triton.
• It is the coldest planet.
• It is the slowest to move around the sun.
• Its diameter is 49,100 kms.
• It is known as the twin of Uranus due to their similarity of size, mass and composition.

__________________
God has sent us to do something special,Life is once for all but not to be Repeated by a pendulum.

Short Note (Solar System)

Lunar Eclipse:

The partial or complete obscuration of light of moon for an observer on the earth is called lunar eclipse. Lunar eclipse takes place when the earth comes in position between the sun and the moon. In this way, the shadow of the earth is cast on the moon and the moon does not get sunlight in this position. Lunar eclipse occurs only when there is full moon. But this does not happen on every full moon because of inclination of the axis of earth to its orbit.

Solar Eclipse:

Solar eclipse occurs when the moon comes in between the Sun and the earth and its shadow is cast across the face of the earth.

The solar eclipse occurs when the moon moves to a position between the Sun and the Earth.

During this process it throws shadow on the earth. This shadow is categorized in umbral and penumbra. The people who are in the umbral region are unable to see the sun at all. This condition is known as the total eclipse of the sun. While the people in penumbra region can see the sun partly this is known as the partial eclipse of the sun.

This happens with the new moon when the moon is in conjunction with the sun. this does not happen at every new moon because of the inclination of the orbit of the moon to the orbit of earth around the sun.

Asteroids:

Asteroids are also known as planetoids. These are small, irregularly shaped rocky objects which orbit the Sun between the orbits of Mars and Jupiter. Asteroids are also known as the minor planets.

Basically the word Asteroid means ―Starlike‖. Ceres asteroid was the first to be discovered.

Meteorites:

Meteorites are small chunks of iron and rock thought to be resulted from collisions between asteroids. They also may be formed when comets disintegrate into fragments. Meteorites enter the earth‘s atmosphere and become a meteor. A meteor is a ―falling star‖ that is usually seen in the sky at night. A meteor will burn up from frictional heating as it enters the atmosphere. Most of the meteors burn up before they reach the earth. If they do not reach the ground they become meteorites. Meteorites can be seen at a distance of 70 miles from the earth. Meteorites are heavy objects which weigh about 60 tons.

Comets:

Comets are those bodies which revolve round the sun. they are mainly composed of ice and dust.
Most comets have three parts which are as under.
i) A solid centre.
ii) A head or round coma, that surrounds the centre and consists of dust particles mixed with frozen water, frozen methane and frozen water, frozen methane and frozen ammonia.

iii) A long tail of dust and gases that escape from the head. Most comets stay near the solar system.Other characteristics of comets are as under:
• Comet is usually about 10 km or 6 miles across.
• Comets are usually made up of ice and dust.
• Millions of comets are present in the solar system.
• Halley‘s comet is the famous example.
• Comets usually move around the sun in the elliptical orbits.

Light Year:

The distance travelled by light at speed of 186,000 miles per seconds in one year is known as a light year. One light year is approximately 9461,000 million kilometres or 5875000 miles. Light year is also used to measure the distance between the galaxies.

Astronomical Unit:

The distance between the Sun and the Earth is called as Astronomical Unit. This unit is also used in the measurement of distances between the heavenly bodies within the solar system. The earth is one A.U away from the Sun and the Pluto is 39 A.U away from the Earth.

Black hole:

Black Hole is a hypothetical region in space which has a big gravitational pull for which no matter or radiation can escape from it. Even it is believed that light cannot escape from it. Black Hole usually likes at the centre of galaxy.

Super Nova:

A Super Nova is an exploding star. At the end of its phase as a Red Giant, a heavy star explodes as a Supernova shining briefly as brightly as a thousand million stars. Recent Supernova was observed on the night of Feb 23, 1987. This occurred in Large Magellanic Cloud.

Nebula:

Nebula is derived from a Greek word which means ―Cloud‖. In the sky there are clouds like objects, which are classified as Nebulae. There are both luminous diffuse nebulae and dark obscuring nebulae over the Milky Way. They are made up of dust and gases.

Aurora:

Aurora or Kutub-i-Raushani is a luminous meteoric phenomenon of electrical character seen in Polar Regions with a tremulous motion and giving forth streams of eight Aurora. It is generally believed that the aurora is actually caused by radiation from the Sun-spots.

__________________
God has sent us to do something special,Life is once for all but not to be Repeated by a pendulum.

Solar Wind:

Solar wind is the stream of electrically charged particles especially protons and electrons, which are emitted by the Sun, predominantly during solar flares and sunspots activity. Some of these particles become trapped in the Earth‘s magnetic field forming the outer Van Allen radiation belt,but some penetrate into the upper atmosphere where they congregate in narrow zones in the
region of the Earth‘s magnetic poles producing aurora displays.

Cosmic Rays:

Cosmic Rays are charged particles moving as fast as the speed of light. Most of the particles are protons, while some are alpha particles and electrons. They travel throughout our galaxy, including the solar system and some strike the earth‘s atmosphere. They can be detected by instruments on the Earth. Nobody knows how cosmic rays are formed. Some of them are formed
by exploding stars or supernova and some come from outside our Galaxy.

Some Important Definitions:

Cosmology:

Cosmology is the science of the cosmos or universe.
OR
Cosmology is the branch of physical science which deals with the Universe.

Universe:

The universe is the sum total of all that exists, or has existed, both in space and time.

Galaxy:

A galaxy is a system of many thousands of millions of stars together with inter-stellar gas and
dust.

OR

Galaxy is a fundamental unit of the universe. It is composed of hundreds of thousands of stars
together with intra-stellar gas and dust.

Star:

Those heavenly bodies which are luminous and produce their own energy by nuclear reactions are called stars.

• Proximal Centauri second nearest after Sun to the Earth.
• Antares is one of the largest stars known.

Solar system:

A tiny system of our galaxy which consists of the /sun, a planet and their satellites, thousands of miniature planets called asteroids, meteoroids, comets, interplanetary dust and plasma.

Satellite:

Those heavenly bodies which revolve round the planets are called satellites.

Eclipse:

In astronomy, the term eclipse simply means the obscuring of one heavenly body by another, particularly that of the sun or a planetary satellite.

Lunar Eclipse:

A condition when the earth comes in between the sun and the moon and throws its shadow on the moon is called lunar eclipse.

Solar Eclipse:

A condition when the moon comes in between the sun and the moon and throws its shadow on the moon is called Solar Eclipse.

Astrology:

Astrology is the interpretation of the influence of planets and stars on human lives.

Asteroids:

Small, irregular shaped rocky objects which orbit the sun between the orbits of Mars and Jupiter are called Asteroids.

Meteorites:

Tiny chunk of material floating in space which can also enter the earth‘s atmosphere and become meteor are known as meteorites.

Comets:

The bodies mainly composed of ice and dust which revolve round the sun are called comets.

Balanced Diet:

• The food which contains all essential food nutrients which are necessary and essential for healthy growth of the body and proper functioning of the whole parts of body.‖

• Food is a complex mixture of chemical substances.
• It performs following useful functions when eaten and absorbed by the body.
i) Produces energy
ii) Promote growth
iii) Repair the tissues
iv) Regulate various processes
• Nutrients are the chemical components of food capable of performing above functions.
• Example: milk is a balanced diet although it does not contain iron.
• Following are the major components of Balanced Diet and their source and functions:

i) Carbohydrates
• Source: Honey, Sugarcane, Wheat, Maize, Potatoes.
• Functions: Provide energy

ii) Fats:

• Source: Butter, Cheese, Soya bean, Mustard etc.
• Functions: Provide Energy

iii) Proteins:
• Source: Meat, Eggs, Fish, Milk, Pulses etc.
• Functions: Essential for growth

iv) Vitamins:

• Source: Fruits and Vegetables.
• Functions: Important for proper physiologic and metabolic functions of the body.

Types:

a) Water Soluble Vitamins: B1, B2, B6, B12, C
b) Fat Soluble vitamins: A, D, E, K

v) Minerals: Minerals are those inorganic substances which play a key role in the maintenance and building of the body tissues. The most important minerals of balanced diet are as under:

• Phosphorus: is necessary for bones and teeth.
• Iron: is an essential component of blood.
• Iodine: is necessary for thyroxin which is secreted from thyroid gland.
• Calcium: is necessary for bone development.

vi) Water:

• Source: Fruits, Vegetables
• Functions: It is constituent of blood, lymph, hormones and other secretions of the body.

__________________
God has sent us to do something special,Life is once for all but not to be Repeated by a pendulum.