Scientific Measure Unit

Scientific Measure Unit

Description

AMPERE

Unit of electric current. It is approximately equal to the flow of 6 x 1018 electrons per second.

ANGSTROM

The unit of wavelength of light is Angstrom. 1 Angstrom = 10-8 cm. There is a bigger unit for measuring the wavelength of infrared light; it is called a milli-micron and is equal to 10-7 cm. Micron =10-4 cm, is a still bigger unit. Bar is the unit of atmospheric pressure; one bar is equal to a pressure of 106 dynes per sq cm.

ATOMIC WEIGHT

The weight of an atom of hydrogen is taken as the standard; the respective weights of the atoms of all other substances are expressed in terms of it. So when it is stated that the atomic weight of iron is 56, it is meant that the atom of iron is 56 times as heavy as the atom of hydrogen.

CALORY

Calory is the unit of heat. It is the amount of heat required to raise the temperature or one gram of water through 1 C.

HORSE POWER

The practical unit of power – the power of an agent which can work at the rate of 550 foot-pounds per second or 33,000 foot-pounds per minute. 1 HP=746 watts.

JOULE

Joule is the unit of work or energy. It is equal to 107 ergs. It is the energy consumed in one second in an electrical circuit through which a current energy of one ampere is flowing against a potential difference of one volt.

KNOT

Knot is a measure to know the speed of a ship.

LIGHT YEAR

A light year is the distance light travels in one mean solar year, at speed of 1, 86,000 miles per second. It is equal to 5,880,000,000,000 miles. It is used as a unit for measuring stellar distances.

NAUTICAL MILE

A unit of distance used in navigation one minute of longitude measured along the Equator. A Nautical Mile is approximately equal to 6, 080 feet.

PRESSURE

The pressure is expressed in pounds weight per sq cm. The pressure of the atmosphere is expressed in millibars. One millibar = 1 dyne per sq cm. If the pressure are very high, they are expressed in multiples of atmospheric pressure. 1 atmosphere is a pressure exerted by a column of mercury 76

cm high at sea level and at a latitude of 45 .

QUINTAL

Metric measure of weight; 100 kilograms = 1 quintal.

VOLT

The unit of potential difference. It is that much potential difference which when applied to the ends of an electrical conductor of resistance one ohm, the amount of energy consumed in the circuit in one second is one Joule (=107 ergs).

WATT

Unit of power – the rate of work done in joules per second; the energy expended per second by an unvarying electric current of 1ampere.

Altimeter

is a special type of aneroid barometer, used in measuring altitudes.

Ammeter

is an instrument to measure the strength of an electric current.

Anemometer

is an instrument to measure the velocity and find the direction of the wind. Audiometer

Audiometer

is an instrument to measure difference in hearing.

Barometer

is used for measuring atmospheric pressure.

Binocular

is an optical instrument designed for magnified view of distant objects by both eyes simultaneously

Calorimeter

is an instrument for measuring quantities of heat.

Chronometer

is a clock to determine longitude of a vessel of sea.

Clinical Thermometer

is a thermometer for measuring the temperature of human body.

Calorimeter

is an instrument for comparing intensities of colour.

Commutator

is an instrument to change of reverse the direction of an electric current. In dynamo used to convert the alternating current into direct current.

Computer

is a technical device designed to find instantaneous solutions of huge and complex calculation based on the information already fed.

Dynamo

is a device for converting mechanical energy into electrical energy.

Electroscope

is an instrument for detecting the presence of electric charge.

Galvanometer

is an instrument for measuring electric current.

Hydrometer

is an instrument for measuring the relative density of liquids.

Hydrophone

is an instrument for measuring sound under water.

Hygrometer

is an instrument for measuring the relative humidity of the atmosphere.

Hygroscope

is an instrument to show the changes in atmospheric humidity.

Lactometer

is an instrument for measuring the relative density of milk.

Micrometer

is an instrument used for accurately measuring small distances or angles

Manometer

is instrument to measure the pressure of gases.

Magnetometer

is an instrument used to compare the magnetic moments and fields,

Mariner’s Compass

is an apparatus for determining direction, graduated to indicate 33 directions. The “N” point on the dial indicates north pole and the “S” point, south pole.

Microscope

is an instrument for magnified view of very small objects.

Periscope

is an apparatus for viewing objects lying above the eye level of the observer and whose direct vision is obstrcists of atube bent twice at right angles and having plane mirrors at these bends inclined at angles of 45 degree to the tube

Photometer

is an instrument for comparing the luminous intensity of the sources of light.

Planimeter

is a mechanical integrating instrument to measure area of a plane surface.

Pyknometer

is an instrument used to measure the density and co-efficient of expansion of liquid.

Pyrheliometer

is an instrument for measuring solar radiations.

Pyrometers

are thermometers to measure high temperatures.

Quadrant

is an instrument for measuring altitudes and angles in navigation and astronomy.

Quartz clock

is a highly accurate clock used in astronomical observations and other precision work

Radio micrometer

is an instrument for measuring heat radiations.

Rain gauge

is an instrument for measuring rainfall.

Refractometer

is an instrument used to measure the refractive index of a substance.

Resistance thermometer

is used for determining the electrical resistance of conductor

Salinometer

is a type of hydrometer used to determine the concentration of salt solutions by measuring their densities.

Seismograph

is an instrument used for recording the intensity and origin of earthquake shocks.

Sextant

is an instrument used for measurement of angular distances between two objects

Spectroscope

is an instrument used for spectrum analysis

Spectrometer

is a type of spectroscope so calibrated as to make it suitable for the precise measurement of refractive indices

Spherometer

is an instrument used for accurately measuring the curvature of spherical objects.

Sphygmomanometer

is an apparatus for measuring blood pressure.

Spring balance

is used to measure the mass of a body. It is preferred only when quick but approximate determinations are to be carried out.

Stereoscope

is an optical device to see two dimensional pictures as having depth and solidity.

Stethoscope

is a medical instrument for hearing and analyzing the sound of heart and lungs.

Stroboscope

is an instrument used for viewing the objects moving rapidly with a periodic motion and to see them as if they

were at rest.

Tangent galvanometer

is an instrument for measuring the strength of direct current.

Telemeter

is an apparatus for recording physical events happening at a distance

Teleprinter

is a communication medium for automatic sending, receiving and printing of telegraphic message from distant places

Telescope

is an instrument for viewing distant objects as magnified

Television

is an instrument used for transmitting the visible moving images by means of wireless waves

Thermometer

is an instrument to measure the temperature.

Thermoscope

is used for measuring the temperature change (approximately) of the substances by nothing the corresponding change in volume.

Thermostat

is an automatic device for regulating constant tempera-tures.

Transistor

is a small device which may be used to amplify currents and perform other functions usually performed by a thermionic value.

Vernier

is an adjustable scale with marking of 10 sub-div isions of one-tenth of an inch or any other suitable marking for measuring small sub-divisions of scale

Viscometer

is an instrument for measuring the viscosity, i.e. the property of resistance of fluid to relative motin within itself

Common S.No. Name 1

2

Zoological Name

Causative Organism

Disease

Mosquitoes

Anopheles sps

Plasmodium

Malaria

Mosquitoes

Culicine sps

Wuchereria bancrofti

Mosquitoes

Stegomyia sps

Flavovirus Fibricus

Mosquitoes

Aedes aegypti

Dengue Virus

Rat Flea

Xenopsilla Cheopsis

Pasteurella Pestis

Bubonic plague

Rat Flea

Xenopsilla sps

R. Typhi

Endemic typhus

Flies

Musca sps

1. Shigella sps

Bacillary

Flies

2. salmonella typhi

dysentery

Flies

3. Salmonella paratyphi

Typhoid fever

Paratyphoid fever Infectious Hepatitis type Avirus hepatitis

Flies 3

Sand fly

Phlebotomus Papatasi

Virus

Sand fly fever

Sand fly

Phlebotomus

Leishmania donovani

Kala azar

4

Body louse

Pediculus

Body louse

Rickettsia prowazeki

Trench fever

R. Quintana Scrub typhus (Tsutsugamushi fever)

5

Mite

Trombicula akamushi

6

Itch mite

Sarcoptes scabieri

Scabies

R. Tsutsugamushi

7

Tick fever

Amblyomma sps

R. rickettsiae

Rock mountain Spotted Theileriosis

8

House fly

Musca domestica

Vibrio cholerae

Cholera

E. coli

Infantile diarrhoea

House fly 9 10

Bed bug Tse-tse fly

Cimex Glossina palpalis

Relapsing fever Trypanosoma gambiense

Sleeping sickness

S.No.DiseasePathogenHabitatMain SymptomsMode of InfectionIncubation Period1CholeraVibrio comma (V. cholerae)IntestineSevere diarrhea and vomitingBy contaminated food and water2 to 3 days2Diarrhoeal diseasesShigella dysenteriae, Salmonella, Escherichia coil, CampylobacterIntestineDiarrheaBy contaminated food and water, Hands, fomite3DiphtheriaCorynebacterium diphthriaeMucous membrane of nose, throat & tonsilsSore throat, difficulty in breathingBy oral & nasal discharges2 to 5 days4GonorrhoeaNeisseria gonorrhoeaeUrinogenital mucosaBurning sensation in micturitionBy sexual contact2 to 5 days5LeprosyMycobacterium lepraeMycobacterium lepraeSkin mucous membranes, peripheral nervesHypopigmented skin patches, ulcers, eformity of digitsLong and close contact with patients2 to 5 days6PlaguePasteurella pestisBlood and lymphPainful pubo of lymph nodesBy rat-flea bite2 to 6 days7PneumoniaDiplococcus pneumoniaeLungsDifficulty in breathingBy patient’s Sputum1 to 3 days8Syphilis Treponema pallidiumOral, genital, rectal mucosaLesionsBy contact3 Weeks9Tetanus (Lockjaw)Clostridium tetaniTissuesPainful muscular spasms and paralysisThrough wounds and burns4 days to 3 weeks10TuberculosisMycobacterium tuberculosisLungsCough, bloody sputum, chest painBy patient’s SputumVariable11TyphoidSalmonella typhiIntestineConstant feverBy contaminated food and water1 to 3 Weeks12Whooping cough (pertusis)Bordetella pertussisRespiratory tractSevere coughing characteristic gasping ‘whoop’By throat discharges and contact10 to 16 days

MEDICAL INVENTIONS Inventor Inventions

Jean-Baptostc Denys William Harvey Rene Laennec Samuel Guthrie Alexander Wood Joseph Lister Sir Thomas Alllbutt Robert Koch Klebs N Loffler Scipione Riva-Rocci

Dr Felix Hoffman K Landsteiner William Einstoven Frederick Banting/Charles Best Alexander Fleming Willem Kolff Ian Donald Carl Djerassi John P. Merril Wilson Greatbatch Christian Barnard Godfrey Hounsfield Vaccines Edward Jenner

Blood Transfusion (1625) Blood Circulation (1628) Stethoscope (1819) Chloroform (1831) Hypodermic Syringe (1853) Antiseptics (1867) Clinical Thermometer (1867) Cholera and TB germs (1883) Diphtheria Germs (1884) Sphygmomanometer (1896) Aspirin (1899) Blood Group (1902) Electrocardiogram (ECG) (1903) Isolated Insulin (1921) Penicillin; it paved the way for antibiotics (1928) Kidney Dialysis Machine (1944) Ultrasound (1950) Contraceptive Pill (1951) Organ Transplant (1953) Heart Pacemaker (1960) Heart Transplant (1967) CAT Scanner (1973) Vaccine for Small Pox

(1796) Louis Pasteur Emil Adolf Von Behring & Shibasaburo Kitasato Charles Nicolle Albert Calmette & Camille Guerin John F Enders & Thomas Peeble Albert Buce Sabin Jonas Salk

Vaccine for Cholera (1880)/Rabbies (1885) Vaccine for Diphtheria and Tetanus Vaccine for Typhus (1909) Vaccine forTB (1922) Vaccine for Measles (1953) Oral Polio Vaccine (1955) Vaccine for Polio (1955)

Blood Groups : It is the grouping of people whose blood may be mixed without clumping of blood vessels. A, B, AB and O are the main four groups. The group AB can receive any blood and is called universal receiver. The group O can be given to any group (universal donor), group A can receive only A (besides O), B can receive only B (besides 0) and O can receive O. These groups were identified by Karl Ladsteiner.

Donors of Blood 1. Group AB may give blood to AB. 2.

Group A may give blood to A and AB.

3.

Group B may give blood to B and AB.

4.

Group O is universal donor for all groups.

Recipients of Blood 1. Group A B is universal recipient. 2.

Group A may receive blood from group A and 0

3.

Group B may receive blood from group B and O.

4.

Group O may receive blood from group O.

Majority of the people around the world have type O positive blood. Percentage of People A+ 34% A6% B+ 8% B1% AB + 3% AB - 1% O + 40% O7% The endocrine system is made up of the endocrine glands that secrete hormones. Although there are eight major endocrine glands scattered throughout the body, they are still considered to be one system because they have similar functions, similar mechanisms of influence, and many important interrelationships. Light enters the eye through the cornea. After passing through the cornea, light travels through the pupil (the black dot in the middle of the eye). The iris—the circular, colored area of the eye that surrounds the pupil—controls the amount of light that enters the eye.

The pupil dilates (enlarges) andconstricts (shrinks) like the aperture of a camera lens as the amount of light in the immediate surroundings changes. The iris allows more light into the eye when the environment is dark and allows less light into the eye when the environment is bright. The size of the pupil is controlled by the action of the pupillary sphincter muscle and dilator muscle. Behind the iris sits the lens. By changing its shape, the lens focuses light onto the retina. The retina contains the cells that sense light (photoreceptors) and the blood vessels that nourish them. The most sensitive part of the retina is a small area called the macula, which has millions of tightly packed photoreceptors (the type called cones).

Light receptor cells called photoreceptors are two groups: a) the rods and b) the cones. The rods respond to shades of light - they 'see' in black and white. The cones respond to colours of light. There are 3 exciting varieties - blue, green and red. So the red cones respond to red light, and so on. Each photoreceptor is linked to a nerve fiber. The nerve fibers from the photoreceptors are bundled together to form the optic nerve. This retinal image is not the same as the object that is being looked at. The image is inverted.

The photoreceptors in the retina convert the image into electrical signals, which are carried to the brain by the optic nerve. The brain then translates the electrical signals into the images we see.

Some glands also have non-endocrine regions that have functions other than hormone secretion. For example, the pancreas has a major exocrine portion that secretes digestive enzymes and an endocrine portion that secretes hormones. The ovaries and testes secrete hormones and also produce the ova and sperm. Some organs, such as the stomach, intestines, and heart, produce hormones, but their primary function is not hormone secretion. GLAND Adrenals

Adrenals/ovaries (women) Adrenals/testes (men) Pancreas

HORMONE(S) Cortisol Aldosterone DHEA (Dehydroepiandrosterone) testosterone estrogens - E1 (estrone), E2 (estradiol), E3 (estriol) testosterone estrogens insulin glucagon

GLP-1 Thyroid T4 (thyroxine), T3 (triiodothyronine) Pituitary GH (growth hormone) ACTH (adrenocorticotrophic hormone) prolactin TSH (thyroid stimulating hormone) LH (luteinizing hormone) FSH (follicle stimulating hormone) Parathyroids PTH (parathyroid hormone) Kidneys Vitamin D DISEASES AND AFFECTED ORGANS Filariasis Feet Securvy Skin and BLood Cyastritis Stomach Eczema Skin Appendicitis Appendix Rickets Joints of children,s Bones Trachima Eyes Cholera Stomach Rabies Brain Pneuminia Lungs Malaria Goitre Asthma Diabetes Polio Typhoid Mumps Diphtheria Jaundice Atherosclerosis Gengivitis, Pyorrhoea Osteomyelitis

Liver and RBCs Thyroid Respiratory tract Pancreas Nervous system, limbs Intestine Salivary glands Throat Liver Heart and blood vascular system Gums Vertebral Column

Vaccine Small pox

Cholera

Diphtheria and tetanus

TB vaccine

Discovered by Edward Jenner (1786) of Gloucestershire made the first, successful small pox vaccination. Louis Pasteur (1880) of France prepared the first Cholera vaccine. Emil Adolf Von Belming and Shibasaburo Kitasato of Germany and Japan respectively(1891) developed anti-toxins to treat diphtheria and tetanus.

Leon Calmette and Camille Guerin (1992) Paris, developed the first TB vaccine. Polio vaccine Jonas E. Salk (1954) Pittsburgh (US). Oval Polio Vaccine Albert Bruce Sabin (1955) US Measles vaccine John F. Enders (1960) USA Rabies Vaccine Typhus Vaccine Charles Nicolle (1909) France. Vitamins serve crucial functions in almost all bodily processes (immune, hormonal and nervous systems) and must be obtained from food or supplements as our bodies are unable to make vitamins. There are thirteen vitamins classified as either water soluble (C and B complex) or fat soluble (A, D, E and K).

Fat Soluble Vitamins Fat-soluble vitamins are absorbed, together with fat from the intestine, into the circulation. Any disease or disorder that affects the absorption of fat, such as coeliac disease, could lead to a deficiency of these vitamins. Once absorbed into the circulation these vitamins are carried to the liver where they are stored. Vitamins A, D, E and K make up the fat soluble vitamins. Vitamins A, D and K are stored in the liver and vitamin E is distributed throughout the body's fatty tissues. Water Soluble Vitamins Water-soluble vitamins, such as Vitamin C and the B vitamins are stored in the body for only a brief period of time and are then excreted by the kidneys. The one exception to this is vitamin B12, which is stored in the liver. Water-soluble vitamins need to be taken daily. Vitamin C (ascorbic acid) and the B complex group make up the nine water soluble vitamins. The B complex group comprises of vitamins: 

B6 (pyridoxine)



B1 (thiamine)



B2 (riboflavin)

B12 (niacin, pantothenic acid, biotin, folic acid and cobalamin) Vitamin sources, uses and deficiency problems Vitamin A (fat-soluble)  Sources: Dairy products, eggs, liver. Can be converted by the body from the beta-carotene found in green vegetables, carrots and liver. 

Uses: Maintains the health of the epithelium and acts on the retina's dark adaptation mechanism. 

Deficiency leads to: Keratinisation of the nasal and respiratory passage epithelium, night blindness 

Vitamin B1 (thiamine) (water-soluble)  Sources: Yeast, egg yolk, liver, wheatgerm, nuts, red meat and cereals 

Uses: Carbohydrate metabolism

Deficiency leads to: Fatigue, irritability, loss of appetite; severe deficiency can lead to beri-beri 

Vitamin B2 (riboflavin) (water-soluble)  Sources: Dairy products, liver, vegetables, eggs, cereals, fruit, yeast 

Uses: Intracellular metabolism

Deficiency leads to: Painful tongue and fissures to the corners of the mouth, chapped lips 

Vitamin B12 (water-soluble)  Sources: Liver, red meat, dairy products and fish Uses: Essential for manufacturing of genetic material in cells. Involved in the production of erythrocytes 



Deficiency leads to: pernicious anaemia

Vitamin C (ascorbic acid) (water-soluble)  Sources: Green vegetables and fruit Uses: Essential for the maintenance of bones, teeth and gums, ligaments and blood vessels. It is also necessary for ensuring a normal immune response to infection 



Deficiency leads to: Scurvy

Vitamin D (fat-soluble)  Sources: Fish liver oils, dairy produce. Vitamin D is formed in the skin when it is exposed to sunlight Uses: Has a role in the absorption of calcium, which is essential for the maintenance of healthy bones 



Deficiency leads to: Rickets

Vitamin E (fat-soluble)  Sources: Pure vegetable oils; wheatgerm, wholemeal bread and cereals, egg yoke, nuts sunflower seeds Uses: Protects tissues against damage; promotes normal growth and development; helps in normal red blood cell formation 



Deficiency leads to: May cause muscular dystrophy

Vitamin K (fat-soluble)  Sources: Green vegetables



Uses: Used by the liver for the formation of prothrombin

Deficiency leads to: Bleeding due to delayed clotting times caused by lack of clotting factors. Patients may show signs of bruising easily and have nosebleeds. Daily Requirements 

Vitamins contain no useful energy for the body but they do link and regulate the sequence of metabolic reactions that release energy within the food we consume. Vitamins cannot be made in the body and must be obtained in our diet. A well balanced diet provides an adequate quantity of all vitamins regardless of age and level of physical activity. The recommended daily requirements (RDR or RDA) for men, women are shown in the Table below. These requirements should be easily met if a balanced diet is adhered to; however, there are groups that may be at greater risk of developing vitamin deficiencies than others. These include those on restricted diets, patients who have digestive disorders that affect the absorption of fat, patients on lipidlowering medication and those whose dietary choices are affected by financial or for conscientious reasons (Trounce and Gould, 1997). For these groups there may be advantages in taking a general or specific vitamin supplement following advice from a doctor or nutritionist. However, for those on a balanced diet there is little to be gained from taking additional vitamins (NHS Direct Online, 2003). Vitamin

Men

Women

A

0.7mg

0.6mg

B1

1.0mg

0.8mg

B2

1.3mg

1.1mg

Nicin

19mg

15mg

B6

1.4mg

1.2mg

Pantothenic acid 5mg

5mg

Folic acid

0.2mg

0.2mg

Biotin

0.03mg 0.1mg

B12

0.002mg 0.002mg

C

40mg

40mg

D

0.01mg 0.01mg

E

10mg

8mg

K

0.8mg

0.06mg

Toxicity of Vitamins Fat soluble vitamins should not be consumed in excess as they are stored in the body and an excess can result in side effects. An excess of vitamin A may result in irritability, weight loss, dry itchy skin in children and nausea, headache, diarrhea in adults. An excess of water soluble vitamins should not result in any side effects as they will disperse in the body fluids and voided in the urine. Free Radicals Electron leakage in the electron transport system results in approximately 2 to 5% of oxygen containing free radicals like superoxide, hydrogen peroxide and hydroxyl. The body's level of pentane can be used to monitor the amount of free radicals. Exercise increases the production of free radicals and a build up of free radicals increases the potential for cellular damage to many biological substances. Research indicates that the body's natural defences of a well nourished athlete are adequate in response to increased amounts of free radicals. Available research indicates that if supplements can be beneficial in combating free radicals then vitamin E may be the most effective. Vitamin and mineral interactions Many vitamins and minerals interact, working alongside each other in groups e.g. a good balance of vitamin D, calcium, phosphorus, magnesium, zinc, fluoride, chloride, manganese, copper and sulphur is required for healthy bones.

Many of them can enhance or impair another vitamin or mineral's absorption and functioning e.g. an excessive amount of iron can cause a deficiency in zinc.

c

Age-Related Macular Degeneration:Age-related macular degeneration (AMD) is the physical disturbance of the center of the retina called the macula.

Bulging Eyes: Bulging eyes, or proptosis, occurs when one or both eyes protrude from the eye sockets due to space taking lesions such as swelling of the muscles, fat, and tissue behind the eye. Cataracts: Cataracts are a degenerative form of eye disease in which the lens gradually becomes opaque and vision mists over.

Cataracts in Babies: In rare cases, children develop cataracts in the first few years of their lives. CMV Retinitis: CMV Retinitis is a serious infection of the retina that often affects people with AIDS (Acquired Immune Deficiency Syndrome) and that may also affect people with other immune disorders. Color Blindness: Color blindness is not actually blindness in the true sense but rather is a color vision deficiency—people who are affected by it simply do not agree with most other people about color matching. Crossed Eyes (Strabismus): Crossed eyes (or strabismus) occur when a person's eyes are not able to align on the same point at the same time, and appear to be misaligned or pointed in different directions. Diabetic Macular Edema: Diabetic Macular Edema, DME, is caused by fluid accumulation in the macula. Patients with DME typically experience blurred vision which can be severe. Eye Floaters and Eye Flashes: Floaters are small specks or clouds that move across your field of vision—especially when you are looking at a bright, plain background, like a blank wall or a cloudless blue sky.

Glaucoma:Glaucoma occurs when a build-up of fluid in the eye creates pressure, damaging the optic nerve. Keratoconus: When the cornea in the front of the eye, which normally is round, becomes thin and cone shaped. Lazy Eye: Commonly known as lazy eye, amblyopia is poor vision in an eye that does not receive adequate use during early childhood. Low Vision: Whenever ordinary glasses or contact lenses don't produce clear vision, you are considered to have low vision. Ocular Hypertension: Ocular hypertension is an increase in pressure in the eye that is above the range considered normal. Retinal Detachment: When the retina detaches, light sensitive membrane in the back of the eye becomes separated from the nerve tissue and blood supply underneath it.

Uveitis: Uveitis is the inflammation of the inside the eye, specifically affecting one or more of the three parts of the eye that make up the uvea. Humans, as you know, have 23 pairs of chromosomes, such that each pair is made up of homologous chromosomes. Cells that have this type of arrangement of their chromosomes, meaning, cells that have pairs of chromosomes, are called diploid. Some organisms are composed of cells with only one of each type of chromosome. These cells do not have homologous chromosomes and are called haploid. Some other organisms contain cells that are made up of many of each type of chromosome, so they have 3 or 4 or 6 or whatever homologous chromosomes! These are called polyploid. Different organisms contain different numbers of chromosomes. The number of different types of chromosomes is represented by "N." In a haploid cell, where no pairs of chromosomes are found, the number of chromosomes that it has is simply N. In a diploid cell, the number of chromosomes is 2 times the number of different types of chromosomes, because it has pairs of chromosomes. So the

total number of chromosomes in a diploid cell is 2N. Humans have 46 chromosomes in total. But we also are diploid. So we have 23 pairs of chromosomes (only 23 different types of chromosomes). A diploid organism containing 28 chromosomes would have N = 14 (because 2N = 28). What does chromosome number have to do with cell division? Meiosis, as you read in the introduction for this lesson, is the way we make our gametes. A man and a woman each have 46 chromosomes. To have a child through sexual reproduction, they have to jumble up their genes and combine them together using their gametes. If the man put all of his 46 chromosomes in his sperm and the woman put all of her 46 chromosomes in her egg, when the sperm and the egg combined, the zygote would have 92 chromosomes! That is way too many! The zygote could not develop into a person. So, instead, the man and woman have to only put half the number of chromosomes into each gamete. That means that the sperm would get 23 chromosomes, the egg would get 23 chromosomes, and the zygote would end up with the correct number of chromosomes, 46, after fertilization. To reduce the number of chromosomes from 46 to 23 in the gamete, the gamete has to be made through meiosis. And, now that you know a lot about homologous chromosomes, it should make sense to you that the only way to cut down the number of chromosomes while still ensuring that each parent gets to contribute an allele to each gene, is to only give one of each pair of chromosomes. When we do that, we take our diploid cells and make haploid gametes out of them. Therefore, humans do have some haploid cells-- but they are all located in our gonads (testes and ovaries). There are no haploid skin or liver cells. And, also, that means that if we are going to make new cells (the gametes), but make them different from the parent cell (haploid, not diploid, gametes), we can't use mitosis to make them. And Pasteur showed us that we can't wait for spontaneous generation to make them. So we need to use another method of cell division... and that method is meiosis. So, meiosis serves to make haploid cells out of a diploid one. Common Name

Genus and Species

Diploid Chromosome Number

Buffalo

Bison bison

60

Cat

Felis catus

38

Cattle

Bos taurus, B. indicus

60

Dog

Canis familiaris

78

Donkey

E. asinus

62

Goat

Capra hircus

60

Horse

Equus caballus

64

Human

Homo sapiens

46

Pig

Sus scrofa

38

Sheep

Ovis aries

54

The process, by which waste product of metabolism from the system of an organism are eliminated from the body. Organs of the Excretory System in Animals: Lungs – removal of excess carbon dioxide Liver – produces urea and uric acid as a by-product of the breakdown of proteins Skin – removal of excess water, salt, urea and uric acid Urinary System – kidneys filter the blood to form urine, which is excess water, salt, urea and uric acid. Excretion in insects: Insects excrete carbon dioxide and uric acid crystals. Uric acid being a nitrogenous waste product is excreted by the malpighian tubules which are found between the junctions of the mid gut projecting into the blood filled cavity. Excretion in annelids: Excretion in the annelids such as the earthworms is carried out by the niphridia which are found in each segment. They release the waste products through the opening s found on the body surface Excretion in birds: Birds excrete carbon dioxide and uric acid. They use the lungs to excrete carbon dioxide and the kidney to excrete uric acid. Excretion in plants: The main excretory products include water and oxygen. These wastes diffuse out of the plant through the stomata and lenticels of stems as they are formed. Other plant wastes include; tannins, alkaloids, anthocyanins which are converted into insoluble compounds like granules and oil droplets which remain in the cells and are got rid of when certain parts of the plants e.g fruits, leaves and flowers fall off from the plants. Excretion in Higher Plants:

Green plants utilize carbon dioxide for photosynthesis which is a metabolic waste product of respiration. Some of the methods of excretion in plants are As follows. 1. Resins, latex, rubber and gums are exuded from various parts of the plant body. 2. In some deciduous plants, the excretory matter is thrown out when the leaves fall. 3. In some plants, tannin is stored in the bark and woody part of the trunk. Due to this the wood appears dark. 4. In the different parts of the plant body, crystals of some chemical substances are set aside, for example calcium carbonate crystals in the leaf of fig, calcium oxalate crystals in the leaf of colocasia. These excretory materials do not harm the plant. Saprophytic plants such as Mucor, Rhizopus and Penictllium excrete their wastes through diffusion. These products maybe poisonous, however many have found use in everyday life of humans, such as latex which is used to produce gloves and clothing. Excretion in plants differs from that in animals because of the following reasons 1. Plants have got a lower metabolic rate compared to animals therefore the rate of accumulation of metabolic waste is very low 2. Plants are autotrophs and therefore synthesize their own organic requirements according to the demand for them. There are never excess proteins in plants therefore very little excretion of nitrogenous wastes 3. Plants have a capacity to store excretory products in some structures where they can be lost at a later stage e.g. fruits, flowers, leaves, barks etc. 4. Much of the plant structure is based on carbohydrate and not protein. The products of carbohydrates carbon dioxide and oxygen can be used in photosynthesis as raw materials. The oxygen given out as a byproduct of photosynthesis can be used in respiration Osmoregulation in plants: Plants are divided into four main groups depending on the amount of water available to them. They are; halophytes, mesophytes and hydrophytes, xerophytes. Hydrophytes: These are plants which live partially or completely submerged in water. They have thin or no cuticle at all, no vascular tissue and reduced root systems because water is readily available to them, they also have many stomata on the upper surface.

Halophytes: These are plants that live in salty waters; they have special cells which have a higher concentration of solute than those of the ordinary plants. As a result they are able to take up water in the normal way Mesophytes: These are plants which grow in normal water well watered soils and water lost by transpiration is replaced by absorption. They have no special means of conserving water although most of them have a well developed root system. Xerophytes: These are plants which live in arid conditions such as deserts, and have a problem of dehydration. They have the following adaptations for their survival 1. Some xerophytes have thick waxy cuticle impermeable to water e.g. cactus 2. Some have leaves modified into thorns or spines to reduce the surface area which minimizes on the rate of transpiration 3. Some shed off their leaves (deciduous) to reduce on the transpiration through the leaves 4. Some roll their leaves to trap still and damp air that reduces transpiration. 5. Some have sunken stomata which are guarded by hairs, the hair traps moisture which reduces on the rate of transpiration 6. Some have succulent tissues like stems which store water 7. They have a well developed tap root system for absorbing water from deep areas Archimedes' Principle: It states that a body, when immersed in a liquid, experiences an upward thrust equal to the weight of the liquid displaced by it. Avogadro's Hypothesis: It is a modification of Berzelius' hypothesis. It states that equal volumes of all gases under similar conditions of temperature and pressure contain equal number of molecules. Avogadro's law is applicable only to gases. Boyle's Law: states that the volume of certain gas is inversely proportional to the pressure at a constant temperature. In other words the product of pressure and volume remains constant provided the temperature is kept constant i.e., P x V = a constant if T remains the same. Charles's Law: It states that at constant pressure all gases expand by 1/273 of their

volume at 0°C for a rise in temperature of 1°C i.e., the volume of a given mass of gas at constant pressure is directly proportional to the absolute temperature. Dulong and Petit's Law: states that the product of atomic weight and specific heat of solid elements is nearly equal to 6.4 i.e., At wt. x sp. heat = 6.4 approx. Gay-Lussac's Law of combining volumes: Gases react together in volumes which bear simple whole number ratios to one another and also to the volumes of the products, if gaseous—all the volumes being measured under similar conditions of temperature and pressure. Graham's Law of Diffusion: states that the rates of diffusion of gases are inversely proportional to the square roots of their densities under similar conditions of temperature and pressure. Kepler's Law: According to this law, a line drawn from the sun to a planet, moving around it, sweeps over a fixed area in a given interval of time. Law of definite proportions: A chemical compound is always found to be made up of the same elements combined together in the same ratio by weight. Law of Floatation: for a body to float, the following conditions must be fulfilled: (1) The weight of the body should be equal to the weight of the water displaced. (2) The centre of gravity of the body and that of the liquid displaced should be in the same straight line. Lenz's Law: When there is change in the magnetic flux linked with a circuit, the electric current induced in the circuit will have a magnetic field opposing the change producing it. Newton's Law of Universal Gravitation: states that "Every portion of matter attracts or tends to approach every other portion of matter in the universe with a force proportional to the masses and inversely as the square of the distance."

Newton's First Law of Motion: "A body continues in its state of rest or of uniform motion in a straight line unless compelled by an external force to change that state." Newton's Second Law of Motion: "The rate of change of momentum is proportional to the impressed force and takes place in the direction of the force." Newton's Third Law of Motion: "To every action, there is an equal and opposite reaction." Newton's Law of Cooling: states that the rate of loss of heat of a hot body is directly proportional to the difference of temperature between the body and the surroundings and is independent of the nature of the body. Ohm's Law: states that the ratio of the potential difference between the ends of a conductor and the current flowing in the conductor is constant, e.g., for a potential difference of E volts and a current I amperes, the resistance R, in ohms is equal to E/I. Principle of conservation of energy: It states that, in any system, energy cannot be created or destroyed; the sum of mass and energy remains constant. Snell's Law: It states that the ratio of the sine of angle of incidence to the sine of the angle of refraction remains constant for any two given media. Specific heat of substance: The quantity of heat required to raise the temperature of 1 gram. of a substance through 1°C.

Sound - Important Points -Properties, Characteristics, Types, Speed, ProductionGeneral Knowledge & Awareness  Sound waves are longitudinal mechanical waves. Sound waves are produced by compression and rarefaction of the particles of the medium.  Sound is a form of energy that causes the sensation of hearing.  Sound needs a medium to travel. Sound travels through gases, liquids and solids. Sound does not travel through vacuum.  Sound waves are reflected, refracted, and diffracted, and exhibit interference



The speed of sound is the maximum in solids, less in liquids and the least in

gases. 

Sound cannot travel through vacuum. In humans, sound is produced by the voice box or the Larynx. Vocal cords in the larynx vibrate and produce sound.  Sound wave always needs an fluid medium to be heard, though it can travel through any material medium but to have an effect on our eardrums a fluid medium is necessary.  Sound Travel with a speed of 332 m/s at 0 C. The denser the medium, the greater the speed of sound whereas the opposite is true of light.  The sound waves have only the characteristics of waves, whereas light has a wave particular duality in nature. They exhibit properties of both waves and particles and are said to be composed of packets of light called photons  The speed of propagation of the sound waves is dependent on the wave frequency. This implies that there is a medium and the medium has atoms, molecules, or some structure. The dependency of the speed of propagation on frequency also implies that there is a minimum wavelength. There is a frequency cut-off. Characteristics of sound waves:

Sound waves have following three characteristics. Intensity: Intensity of sound at any point of space is defined as amount of energy passing normally per unit area held around that point per unit time. SI unit of intensity is watt/m2 . Intensity of sound at a point is, (i) inversely proportional to the squire of the distance of point from the source.

(ii) Directly proportional to squire of amplitude of vibration, squire of frequency and density of the medium. Due to intensity, a sound appears loud or faint to the ear. Actually, the sensation of the sound perceived in ear is measured by another term called loudness which depends on intensity of sound and sensitiveness of the ear. Unit of loudness is bel. A practical unit of loudness is decibel (dB) which of equal to1/10th of bel. Another unit of loudness is phon. Pitch: Pitch is that characteristic of sound which distinguishes a sharp sound from a grave (dull or flat) sound. Pitch depends upon frequency. Higher the frequency, higher will be the pitch and shriller will be the sound. Lower the frequency, lower will be the pitch and grave will be the sound. Quality: Quality is that characteristic of sound which enables us to distinguish between sounds produced by two sources having the same intensity and pitch. The quality depends upon number, frequency and relative intensities of overtones. Effect of Pressure, Temperature & Humidity on Sound:

Effect of pressure on speed of sound: The speed of sound is independent of pressure i.e. speed remains unchanged by the increase or decrease of pressure. Effect of temperature on speed of sound: The speed of sound increases with the increase of temperature of the medium. The speed of sound in air increases by 0.61 m/s when the temperature increased by 1 C. Effect of humidity on speed of sound: The speed of sound is more in humid air then in dry air because the density of humid air is less than the density of dry air. According to their frequency range, longitudinal mechanical waves are divided into the following categories:

1.

Audible or Sound waves

The longitudinal mechanical wave which lie in the frequency range 20 Hz to 20000 Hz are called audible or sound waves. These waves are sensitive to human ears. These are generated by the vibrating bodies such as tuning fork, vocal cords etc. 2.

Infrasonic Waves

The longitudinal mechanical waves having frequencies less than 20 Hz are called Infrasonic. These waves are produced by sources of bigger size such as earth quakes, Volcano eruptions, meteors, ocean waves and by elephants and whales. Elephants have the ability to emit infrasound to communicate at distances of up to 10 miles (12 35 Hz.). Even tigers emit infrasound. Application/Uses of Infrasonic Waves: Infrasonic waves can carry over long distances [thousands of kilometres] and are less susceptible to disturbance or interference than waves of higher frequencies. A. Medical: (therapeutic devices) - Several studies conducted in Russia and Europe reported that infrasound has therapeutic effects. - Infrasound peumomassage: At 4 Hz, the progression of myopia in school children can be stabilized. - Infrasound phonophersis in antibacterial drugs: In treatment of patients with bacterial keratitis, it is as effective as local instillations of the same drugs. B. Monitoring activities of the atmosphere: Infrasonic waves will be influenced by the atmosphere during its propagation, which is closely related with the distribution of temperature and wind in the atmosphere. By measuring the propagation properties of infrasonic waves generated by natural sources, one can detect some characteristics and rules of the large scale meteorological motions. C. Forecasting natural disasters: Many disasters, such as volcanic eruptions, earthquakes, land-slides and clear-air turbulences, radiate infrasound in advance . By monitoring the infrasound waves , we can forecast these disasters. How Bad are Infrasonic Waves: Infrasound is especially dangerous, due to its strong vibrations, or oscillations. They hug the ground, travel for long distances without losing strength, and are unstoppable. 3.

Ultrasonic Waves

The longitudinal mechanical waves having frequencies greater than 20000 Hz are called Ultrasonic Waves. But certain creatures like dog, cat, bat, and mosquito can detect these waves. Bat not only detect by also produce ultrasonic waves. Humans cannot hear the sound of inaudible range. Applications of Ultrasonic Waves: 1. For sending signals. 2. For measuring depth of sea. 3. For cleaning cloths, aeroplanes and machinery parts of clock. 4. For removing lamp-shoot from the chimney of factories. 5. In sterilizing of a liquid. 6. In Ultra-Sonography.

7. Doppler effect: Doppler effect to assess whether structures (usually blood) are moving towards or away from the probe , and its relative velocity . 8. Whales make use of ultrasounds for communication purposes. Individual pods of whales have their own distinctive dialect of calls, similar to songbirds.

Speed of Sound:

Speed of sound is different in different mediums. In a medium, speed of sound basically depends upon elasticity and density of medium.Speed of sound is maximum in solids and minimum in gases. When sound enters from one medium to another medium, its speed and wavelength changes but frequency remains unchanged. In a medium, the speed of sound is independent of frequency. Medium Carbon dioxide Air (0 C) Air (20 C) Steam (100 C) Helium

Speed of sound (In m/s) 260 332 343 405 965

Alcohol Hydrogen Mercury Water (20 C) Sea Water Copper Iron Glass Granite Aluminum

1213 1269 1450 1482 1533 3560 5130 5640 6000 6420

What is Audible Range of Sound?

Sounds with frequency between 20 Hz to 20,000 Hz are called audible sound. The hearing range of human beings is between 20 hertz to 20,000 hertz. Sound with frequency below 20 hertz and above 20,000 hertz is called sound of inaudible range. Humans cannot hear the sound of inaudible range. Many animals, such as dogs, cats, etc. can hear the sound with frequency above 20,000 hertz How sound is produced by Humans?

Larynx is composed of two stretched membranes; with some gap between them. When air passes through the larynx, the membranes or vocal cords vibrate and produce sound. That is why larynx is also known as sound box. Various Ways Pleasant Sound is Produced:

Some instruments produce sound due to the -vibration of membranes, -vibration of strings, and -vibration of an air column.

The to and fro or back and forth motion of an object is called vibration. The sitar, veena, violin, guitar and ektara are some stringed instruments. The tabla, cymbals, ghatam, kartal and manjira are some instruments that work on the vibration of a membrane. The instruments like the flute and the trumpet produce sound due to the vibration of an air column present in them. Sonar and its Working Principle:

SONAR means SOund NAvigation and Ranging. Sonar is an instrument that use ultrasonic wave for sound ranging. It measures even short time intervals quite accurately. Sonar works on the principle of echo. A strong and short (ultrasonic) sound signal is sent towards the bottom of the ocean. Echo of the signal is then detected and depth of ocean is calculated. What is Echo?

The sound waves received after being reflected from a high tower or mountains is called echo. To hear echo, the minimum distance between the observer and reflector should be 17m (16.6 m). Persistence of ear (effect of sound on ear) is 1/10. Doppler Effect: If there is a relative motion between source of sound and observer. The apparent frequency of sound heard by the observer is different from the actual frequency of sound emitted by the source. This phenomenon is called Doppler Effect. When the frequency between the source and observer decreases, the apparent frequency increases and vice-versa. What is Mach Number?

Mach Number: It is defined as the ratio of speed of sound source to the speed of sound in the same medium under the same condition of temperature and pressure. If match number >1, body is supersonic. If match number >5, body is called hypersonic. If match number < 1 -the body is said to be moving with subsonic speed. Some reasons commonly asked in Exam: 

Children and women produce sound of high frequency and their sound is shriller and of higher pitch. On the other hand, an adult male produces sound of lower frequency and his sound is less shrill and has lower pitch.  A drum produces sound of lower frequency which is less shrill and has lower pitch, while a whistle produces sound of higher frequency which is shriller and is of higher pitch.  A lion produces a sound of lower frequency which is less shrill and has lower pitch, while a bird produces sound of high frequency which is shriller and has higher pitch. However, sound of lion is louder than the sound of a bird.



We know that the speed of light much more than the speed of sound. Due to this, light reaches to us faster than sound. Hence, during lightning we see the streak of light earlier than hearing the sound of thunder.  Due to refraction, sound is heard at longer distance in nights than in day.  Resonance: If the frequency of the imposed periodic force is equal to the natural frequency of a body, the body oscillates with a very large amplitude. This phenomenon is called resonance.  Interference of sound: The modification or redistribution of energy at a point due to superposition of two (or more) sound waves of same frequency is called interference of sound. If two waves meet at a point in same phase, intensity of sound is maximum at that point. Such type of interference is called constructive interference. Similarly, if the two point meet at a point in opposite phase, intensity of sound at that point is minimum. Such type of interference is called destructive interference.  Diffraction of sound: Wavelength of sound is of the order of 1 m. If an objective of that range appears in the path of sound, sound deviates at the edge of obstacle and propagates forward. This phenomenon is called diffraction of sound.  Shock waves: A body moving with supersonic speed in air leaves behind it a conical region of disturbance which spreads continuously. Such a disturbance is called shock waves. These waves carries a huge energy and may even cracks in window panes or even damage a building.  Bow waves: When a motor boat travels faster than sound, then waves just like shock waves are produced on the surface of water. These waves are called bow waves. Some Questions: Which of the following is true? a) Sound waves exhibit interference b) Light waves exhibit interference c) Both the light and sound waves exhibit interference d) Neither sound waves nor light waves exhibit interference. Effects of Refraction of Light 1. A swimming pool always looks shallower than it really is, because the light coming from the bottom of the pool bends when it comes out at the surface due to refraction of light. 2.

A straight stick which is immersed partly in water always looks to be

bent at the surface of water, because the light coming from the stick bends when it comes out at the surface due to refraction of light. 3.

A coin or stone lying at the bottom of a container filled with water

appears to be raised because of refraction of light.

4.

A line or a spot of ink on a paper always appears to be raised when

viewed through the glass slab due to the refraction of light. 5.

Twinkling of stars is due to the refraction of light.

6.

Optical illusions such as mirage and looming are also produced due to

refraction of light.

Essential Conditions for Total Internal Reflection There are two conditions which are essential for total internal reflection. These are: 1.

The light should travel from a denser medium to a rarer medium.

2.

The angle of incidence of light traveling in denser medium should be greater

than the critical angle of the medium Effects of total internal reflection of Light Twinkling of Stars: The light rays coming from a star reaches our eyes after passing through the atmosphere having different air layers of different optical densities. But the optical densities of different layers of air keep on changing continuously due to change in temperature conditions. Due to which, the light rays coming from a star are refracted to different amount at different moments of time, and the path of refracted rays keep on changing. As a result, sometimes more light is refracted towards our eyes

and the star appears bright to us, whereas sometimes less light is refracted towards our eyes and the star appears dim to us. This gives rise to the twinkling effect of a star. The Sun is visible to us 2 minutes before actual sunrise and 2 minutes after the actual sunset: The Sun is visible to us 2 minutes before actual sunrise and 2 minutes after the actual sunset due to atmospheric refraction. Actually when the Sun is slightly below the horizon, then the light rays emitted by the Sun are refracted downwards when passing through the optically rarer air layers into the optically dense air layers of atmosphere. Due to which, the Sun appears to be slightly raised above the horizon and is visible 2 minutes before actual sunrise and 2 minutes after the actual sunset. Mirage : Mirage is an optical illusion which occurs usually in deserts on hot summer days due to atmospheric refraction and total internal reflection of light rays. In mirage, the object such as a tree appears to be inverted as if it is situated on a bank of a pond of water. Looming: Looming is also an optical illusion which occurs usually in very cold regions. In looming, a distant object such as a ship moving in polar areas appears to be hanging in midair due to atmospheric refraction and the total internal reflection of light rays. Brilliance of diamond: The brilliance of a diamond is due to the total internal reflection of light. We know that the refractive index of diamond is 2.42, and the critical angle for diamond is 240. The diamond is cut in such a way so that the light which enters the diamond from any face suffers multiple total internal reflections at the various faces before coming out of the diamond. Due to this, the diamond sparkles. Rainbow (refraction + total internal reflection) DISPERSION OF LIGHT

The dispersion of light is the phenomenon of splitting of a beam of white light into its seven constituent colours when passed through a transparent medium. It was discovered by Isaac Newton in 1666. Newton discovered that light is made up of seven different colours. hus the spectrum is a band of seven colours which is obtained by splitting of white light by a glass prism. The order of colours from the lower end of spectrum is violet (V), indigo (I), blue (B), green (G), yellow (Y), orange (O), and red (R). The sequence of the 7 colours so obtained in a spectrum can be remembered by using the acronym ‘VIBGYOR’. Effects of Dispersion: a) Prisms and rain drops both create rainbows because of this effect. n the case of a rainbow, the droplets of water on the ground act as the prism, refracting the light twice and dispersing it into all of the colors of the rainbow.

b) Rainbow Formation: The formation of rainbow is based on the process of dispersion of light. It is the most enchanting example of dispersion of light which takes place naturally. Usually a rainbow of seven colours is seen in the sky just after the rain when the Sun is shining. The essential condition to see the rainbow is that the observer must stand with his back towards the sun, when seeing the rainbow. Solar system and planets Wiki. The solar system consists of the Sun and 8 planets revolving around it in different orbits. SUN Age: About 5 Billion years Distance: 149.8 Million Kms Diameter: 1,38,400 Kms. Photosphere temperature : 5,770 K Core temperature: 150,000,000 K Absolute visual magnitude: 4.75 Rotation (as seen from the earth at the equator): 25.38 days Rotation (near the poles): 33 days



The sun consists of 71% of Hydrogen, 26.5% Helium and 2.5% of other

elements. 

The rays of the Sun take about 8 minutes to reach the earth.



The Sun resides in one of the Milky Way's outer spiral arms, known as

the Orion–Cygnus Arm or Local Spur. 

Next closest star is the triple star system Alpha Centauri(A, B and C), which is

about 4.4 light years away. 

The stars next closest to the Sun are the red dwarfs Barnard's Star (at 5.9 light

years), Wolf 359 (7.8 light years), and Lalande 21185 (8.3 light years). The largest star within ten light years is Sirius. What is Galactic Year? The Sun lies between 25,000 and 28,000 light years from the Galactic Centre, and its speed within the galaxy is about 220 kilometres per second (140 mi/s), so that it completes one revolution every 225–250 million years. This revolution is known as the Solar System's galactic year.

What are the conditions to be satisfied for planet-hood status? Why Pluto was removed from Planet list, which conditions it satisfied and where it failed? 1. A planet has to orbit the Sun. Pluto does that. 2. A planet needs enough gravity to pull itself into a sphere. Okay, spherical. Pluto’s is spherical.

3. A planet needs to have cleared out its orbit of other objects. Uh oh, Pluto hasn’t done that. For example, planet Earth accounts for a million times the rest of the material in its orbit, while Pluto is just a fraction of the icy objects in its realm. PLANETS Comparison of planets based on size, radius, density, surface gravity: Body Mean Volume Mass Density Surface 9 3 21 (10 km ) ×10 kg g/cm3 gravity radius (Yg) (m/s2) (km) Sun Jupiter Saturn Uranus Neptune Earth Venus

696,000 69,911 58,232 25,362 24,622 6,371.0 6,051.8 (w/o gas) Mars 3,390.0 Mercury 2,439.7

1,412,000,000 1,431,280 827,130 68,340 62,540 1,083.21 928.43

1,989,100,000 1,898,600 568,460 86,832 102,430 5,973.6 4,868.5

1.409 1.33 0.70 1.30 1.76 5.515 5.24

274.0 24.79 10.445 8.87 11.15 9.78033 8.872

163.18 60.83

641.85 330.2

3.94 5.43

3.7 3.7

Moon

21.958

73.5

3.3464

1.625

1,737.1

The inner Solar System is the traditional name for the region comprising the terrestrial planets and asteroids. The four inner or terrestrial planets have dense, rocky compositions, few or no moons, and no ring systems. They are composed largely of refractory minerals, such as the silicates, which form their crusts and mantles, and metals such as iron and nickel, which form their cores. Three of the four inner planets (Venus, Earth and Mars) have atmospheres substantial enough to generate weather; all have impact craters and tectonic surface features such as rift valleys and volcanoes. (1) MERCURY

It is the planet nearest to the earth and smallest one in solar system. Mercury has no natural satellites Average distance to the Sun : 57.6 Million Kms. Diameter : 4,849.6 Kms. Period of revolution

: 88 days

Period of rotation

: 58 days 15 hrs 30 mts. 34sec.

(2) VENUS It is also known as the Morning Star or the Evening Star. It is the brightest of all the planets. is close in size to Earth (0.815 Earth masses) and, like Earth, has a thick silicate mantle around an iron core, a substantial atmosphere, and evidence of internal geological activity. Venus has no natural satellites. It is the hottest planet, with surface temperatures over 400 °C (752°F), most likely due to the amount of greenhouse gases in the atmosphere Diameter : 12,032 Kms. Period of revolution : 225 days Period of rotation : 243 days 14mts. (3) EARTH Surface Area

: 510,100,500 Sq.Kms.

Polar radius

: 6,357 Kms.

Land Surface

: 148,950,800 (29.08%)

Water Surface

: 361,149,700 (70.92%)

Equatorial circumference : 40,075 Kms. Polar circumference Equatorial radius

: 40,008 Kms : 6,377 Kms.

Equatorial Diameter

: 1,22,756 Kms.

Polar Diameter

: 12,714 Kms.

Mean distance from the Sun : 14,95,97,900 Kms. Period of revolution : 365 days 5 hours 48 mts. 45.51 Sec.

Period of rotation : 23 hrs. 56 mts. 4.091 Sec. Escape Velocity from the earth : 11 Km per Sec. (minimum) Some important Data about Earth: The Earth is a sphere but it is not a perfect sphere. It is slightly flattened at the poles and bulges at the equator. The circumference of the earth is approximately 25,000 miles (40,000 Kms).It rotates on its axis once in every 24 hours, spinning from west to east. Besides spinning on its axis, it also moves round the Sun, called the revolution. Its orbit round the Sun is oval or ecliptical. The time taken to complete one revolution is approximately 365¼ days or one year. For convenience, one year is taken as 365 days and the shortfall of ¼ day each year is made good in the Leap Year which consists of 366 days. The Earth’s axis inclined to the plane of its orbit at an angle of 66½ position in the course of its revolution about the Sun, and to the inclination of its axis. The Equator is an imaginary line drawn round the Earth midway between the Poles. There are two other lines, namely, Tropic of Cancer (23½ N) and the Tropic of Capricon (23½ S). The word tropic means, ‘turning place’. The inclination of the Earth’s axis together with its revolution round the Sun is the cause of the varying length of day and night in different parts of the world. On March 21 (Vernal Equinox) and September 23 (Autumnal Equinox) the Sun is over- head at the Equator. On these dates, except at the Poles, (a) days and nights are equal all over the world; and (b) the Sun rises exactly due east and set exactly due west at all places on the Earth’s surface. At the Equator itself days and nights are equal throughout the year. Between March 21 and September 23, when the North Pole is tilted towards the Sun, the days are longer than the nights throughout the Northern Hemisphere and there is continuous daylight at the North Pole. Similar conditions are experienced in the Southern Hemisphere and the South Pole between September 25 and March 21. (4) MARS

Diameter : 6,755.2 Kms. is smaller than Earth and Venus (0.107 Earth masses). Its surface, peppered with vast volcanoes such as Olympus Mons and rift valleys such as Valles Marineris. Its red colour comes from iron oxide (rust) in its soil. Mars has two tiny natural satellites (Deimos and Phobos) thought to be captured asteroids Distance from the Sun : 225.6 Million Kms. Period of revolution

: 687 days

Period of rotation

: 24 hrs 37 mts. 22.663 sec.

Outer planets of Solar System: he four outer planets, or gas giants (sometimes called Jovian planets), collectively make up 99% of the mass known to orbit the Sun (5) JUPITER : This is the largest planet in the solar system. Diameter

: 141,968 Kms.

Distance from the Sun : 772.8 Million Kms. Period of revolution

: 11.9 years

Period of rotation

: 9 hrs 50 mts. 30 sec.

It is composed largely of hydrogen and helium. Jupiter's strong internal heat creates a number of semi-permanent features in its atmosphere, such as cloud bands and the Great Red Spot. Jupiter has 67 known satellites. The four largest, Ganymede, Callisto, Io, and Europa. Ganymede, the largest satellite in the Solar System. Topics To Be Read >>ELEMENTS OF WEATHER >>Deserts - Definition - Types - Deserts in India >>Himalayas of India >>How to measure rainfall in an area? >>Solar System and Planets for Civil Services

(6) SATURN : It was discovered by Galileo. Diameter : 119,296 Kms. Distance from the Sun : 1,417.6 Million Kms. Period of revolution : 29.5 years Period of rotation : 10 hrs 14 mts. least dense planet in the Solar System.

>>Distribution of Temperature and the Heat Zones >>Land forms produced by Internal and External processes of EarthLand forms produced by Internal and External processes of Earth

Saturn has 62 confirmed satellites; two important moons are Titan and Enceladus. Titan, the second-largest moon in the Solar System.

(7) URANUS Diameter

: 52,096 Kms.

Distance from the Sun : 2,852.8 Million Kms. Period of revolution

: 84 years

Period of rotation

: 16 hrs 10 mts.

its axial tilt is over ninety degrees to the ecliptic. Uranus has 27 known satellites, the largest ones being Titania, Oberon, Umbriel, Ariel, and Miranda. (8) NEPTUNE Diameter

: 49,000 Kms.

Distance from the Sun : 4,497 Million Kms. Period of revolution

: 165 years

Period of rotation

: 18 hrs 26 mts.

Neptune has 14 known satellites. The largest, Triton, is geologically active, with geysers of liquid nitrogen (9) PLUTO : It's not a planet anymore. But it is the coldest and smallest of all planets. It is also the most distant one(while it was planet) Diameter : 3,040 Kms. Distance from the Sun : 5,865.6 Million Kms. Period of revolution

: 248 years

Period of rotation

: 6 days 9 hrs and 18 mts.

MOON : Monn is a dead planet. Moon is earth's satellite. Its period of rotation and Period of Revolution are the same. i.e.29.5 days.

Some other Important Points: 

The asteroid belt occupies the orbit between Mars and Jupiter



Ceres (2.77 AU) is the largest asteroid, a protoplanet, and a dwarf planet



Uranus and Neptune are called Ice Giants.



Saturn's ring system is easily observed from Earth.



Eris (68 AU average) is the largest known scattered disc object, and caused a

debate about what constitutes a planet.

What is Kuiper belt? The Kuiper belt is a great ring of debris similar to the asteroid belt, but consisting mainly of objects composed primarily of ice. It extends between 30 and 50 AU from

the Sun. The Kuiper Belt is a disc-shaped region of icy objects beyond the orbit of Neptune -- billions of kilometers from our sun. The makeup of Kuiper Belt Objects is similar to the composition of comets – a mixture of frozen water, ammonia and various hydrocarbons, such as methane. What are Centaurs? The centaurs are icy comet-like bodies with a semi-major axis greater than Jupiter's (5.5 AU) and less than Neptune's (30 AU). The first centaur discovered, 2060 Chiron, has also been classified as comet (95P) because it develops a coma just as comets do when they approach the Sun. What is comet, how is it different from Asteroid? Comets have eccentric orbits so their distance from the Sun varies considerably. The nucleus of a comet is composed of volatile material. When a comet is far from the sun, this material usually stays pristine but when the comet comes closer to the sun, solar radiation and solar winds cause it to lose some volatile compounds from its surface. This gives it a coma i.e. a nebulous appearance and a thin, transient atmosphere, which differentiates it from asteroids. What’s the difference between a comet, asteroid, meteoroid, meteor & meteorite? Comet: A comet is a relatively small solar system body that orbits the Sun. When a comet enters the inner Solar System, its proximity to the Sun causes its icy surface to sublimate and ionise, creating a coma: a long tail of gas and dust often visible to the naked eye. Asteroid: Asteroids are small solar system bodies that orbit the Sun. Made of rock and metal, they can also contain organic compounds. Asteroids are similar to comets but do not have a visible coma (fuzzy outline and tail) like comets do.

Meteoroid: A meteoroid is a small rock or particle of debris in our solar system. They range in size from dust to around 10 metres in diameter (larger objects are usually referred to as asteroids). Meteor: A meteoroid that burns up as it passes through the Earth’s atmosphere is known as a meteor. If you’ve ever looked up at the sky at night and seen a streak of light or ‘shooting star’ what you are actually seeing is a meteor. Meteorite: A meteoroid that survives falling through the Earth’s atmosphere and colliding with the Earth’s surface is known as a meteorite. What is Heliopause? The region surrounding the solar system at which pressure from the outgoing solar wind equals the pressure from the interstellar medium (made up mostly of hydrogen and helium), and the solar wind can penetrate no further. It is considered to be the outer boundary of our solar system S No

Physical Quantity

Units

1 Length

Metre

2 Time

Second

3 Mass

Kilogram

4 Area

Square metre

5 Volume

Cubic metre

6 Velocity

Metre / second Kilogram / Metre

7 Density

Cube

8 Energy

Joule

9 Force

Newton Pascal or Newton /

10 Pressure

Square Metre

11 Frequency

Hertz

12 Power

Watt Newton or

13 Weight

Kilogram

14 Heat

Joule

15 Temperature

Kelvin

16 Resistance

Ohm

17 Electric current

Ampere

Electromotive 18 force

Volt

19 Intensity of Sound

Decibel

20 Power of lens

Dioptre

21 Depth of Sea

Fathom

22 Magnetic Intensity

Orsted

23 Electric Power

Kilo Watt or Watt Metre / Second

24 Acceleration

Square Kilogram Metre /

25 Momentum

Second

26 Work

Joule

27 Impulse

Newton- Second

28 Angular velocity

Radian / Second

29 Viscosity

Poise Newton / Square

30 Surface tension

Metre

Absolute 31 temperature

Kelvin

Electrical 32 conductivity

Ohm / Metre

33 Electric Energy

Kilo Watt hour

34 Charge

Coulomb

35 Magnetic induction

Gauss

36 Luminous flux

Candela

Factor

Prefix

Symbol

10

exa

E

1015

peta

P

1012

18

tera

T

9

giga

G

10

6

mega

M

103

kilo

k

102

hecto

h

deka

da

10-1

deci

d

10-2

centi

c

-3

milli

m

10

-6

micro

m

10-9

nano

n

10-12

10

1

10

0

10

10

pico

p

-15

femto

f

-18

atto

a

10 10

What is Ore? Type of different ores of everyday used metals General Knowledge Labels: general Awareness, Physics & Chemistry at 10:57 PM Posted by Saidul Naik

A mineral or rock, which contains enough of a chemical element to make it economically feasible to mine, is called an ore. A mineral which contains a high enough percentage of a metal for economic extraction is called a metal ore. The recovery of metals from their ores is one area of the field of metallurgy. The separation of the desired element is done by roasting, smelting, electrolysis or various chemical treatments. Important ores of aluminum, iron, manganese, and tin

are oxides; Important ores of antimony, copper, lead, mercury, nickel, silver, and zinc aresulfides. Names of the Elements Aluminium (Al)

Iron (Fe)

Copper (Cu)

Ores (a) Bauxite

Chemical Formulae Al2O3 . 2H2O

(b) Corundum

Al2O3

(c) Kryolite

Na3AlF6

(a) Haematite

Fe2O3

(b) Magnetite

Fe3O4

(c) Iron Pyrite

FeS2

(d) Siderite

FeCO3

(a) Copper Pyrite (b) Copper Glance (c) Malachite

CuFeS2

Zinc (Zn)

(a) Zinc Blende (b) Calamine

Sodium (Na)

(a) Rock Salt (b) Sodium Carbonate (a) Karnalite

Potassium (K)

Cu2S 2CuCO3 . Cu(OH) ZnS ZnCO3 NaCl Na2CO3

(b) Salt Petre

KCI MgCl . 6H2O KNO3

Lead (Pb)

(a) Galena (b) Anglesite

PbS PbCl2

Tin (Sn)

(a) Tin Pyrites

Cu2 FeSnS4

(b) Cassiterite

SnO2

(a) Silver Glance (a) Calverite

Ag2S

(b) Syvanite

AgAuTe2

Mercury (Hg)

(a) Cinnabar (b) Calomel

HgS Hg2Cl2

Magnesium

(a) Dolomite

MgCO3 . CaCO3

Silver (Ag) Gold (Au)

AuTe2

(Mg)

(b) Karnalite

Calcium (Ca)

(a) Lime Stone

KCl MgCl2 . 6H2O CaCO3

(b) Dolomite

MgCO3 . CaCO3

(a) Phosphorite

Ca3(PO4)

(b) Floreapetite

3Ca3(PO4)2CaFe2

Phosphorous (P)

Fact to remember Metal most abundant in earth’s crust Metal which forms amalgam with other elements Metal used in a fuse wire and also in solder Metal used in the filament of a bulb Metal which pollutes the air of cities having large number of vehicles Metal used in the filaments of electric heaters Metal used as radiation shield Metal into which Uranium turns when it loses all its radioactivity Metal used for making boats because it does not corrode by seawater

Name of the metal Aluminium Mercury Lead-tin alloy Tungsten Lead (reason for using unleaded petrol) Nichrome Lead Lead Titanium