2. Explain the structure of Earth and its atmosphere

Crust, outermost layer of Earth. The crust is solid and relatively thin, and it lies below both landmasses and oceans. The dry land of Earth’s surface is called the continental crust. It is about 15 to 75 km (9 to 47 mi) thick. The oceanic crust is thinner than the continental crust. Its average thickness is 5 to 10 km (3 to 6 mi). The crust is very thin in relation to the rest of Earth. Beneath the crust lies a much thicker layer called the mantle, which surrounds Earth’s central core.

The crust has a definite boundary, Moho.In comparison to the crust, the mantle is much thicker. The mantle extends for about 2,900 km (1,800 mi). It consists of an upper mantle and a lower mantle. The solid, outermost section of the mantle and the solid crust together form the lithosphere. The lithosphere is approximately 65 to 100 km (40 to 60 mi) thick and covers the asthenosphere . The asthenosphere is approximately 100 to 350 km (60 to 220 mi) thick. It consists of rocky material that is softer and less rigid than that in the lithosphere. This softer, less rigid state results from higher pressures and temperatures, which cause the rocks partially to melt and become soft.Temperatures in the mantle are high, reaching about 3700° .
Core, innermost part of Earth. The core of Earth extends from beneath the mantle to the very center of the planet. The radius of the core is approximately 3,500 km (2,200 mi). This radius is larger than the radius of the planet Mars. The core forms approximately one-third of Earth’s total mass and about one-sixth of its volume.Core temperatures range from 4000° to 5000°C (7200° to 9000°F). Iron and nickle form it.

for diagram
http://www.windows.ucar.edu/tour/lin.../windows3.html

Atmosphere, mixture of gases surrounding any celestial object that has a gravitational field strong enough to prevent the gases from escaping; especially the gaseous envelope of Earth. The principal constituents of the atmosphere of Earth are nitrogen (78 percent) and oxygen (21 percent). The atmospheric gases in the remaining 1 percent are argon (0.9 percent), carbon dioxide (0.03 percent), varying amounts of water vapor, and trace amounts of hydrogen, ozone, methane, carbon monoxide, helium, neon, krypton, and xenon.

The atmosphere is divided into five layers. It is thickest near the surface and thins out with height until it eventually merges with space.

1) The troposphere is the first layer above the surface and contains half of the Earth's atmosphere. Weather occurs in this layer.
2) Many jet aircrafts fly in the stratosphere because it is very stable. Also, the ozone layer absorbs harmful rays from the Sun.
3) Meteors or rock fragments burn up in the mesosphere.(50 to 90 km)
4) The thermosphere is a layer with auroras. It is also where the space shuttle orbits.
5) The atmosphere merges into space in the extremely thin exosphere. This is the upper limit of our atmosphere.

a very good link on geography.
http://www.windows.ucar.edu/cgi-bin/...ows3.html&fr=f


rgds

5.What is the difference between

(i) BIT and BYTE
(ii) RAM and ROM
(iii) C.U. and A.L.U
(iv) Hardware and Software
(v) Personal computer and mainframe.
BIT
Short for binary digit, the smallest unit of information on a machine. A single bit can hold only one of two values: 0 or 1. More meaningful information is obtained by combining consecutive bits into larger units. For example, a byte is composed of 8 consecutive bits.

BYTE
Abbreviation for binary term, a unit of storage capable of holding a single character. On almost all modern computers, a byte is equal to 8 bits. Large amounts of memory are indicated in terms of kilobytes (1,024 bytes), megabytes (1,048,576 bytes), and gigabytes (1,073,741,824 bytes).

RAM
Pronounced ramm, acronym for random access memory, a type of computer memory that can be accessed randomly; that is, any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers.

ROM
Pronounced rahm, acronym for read-only memory, computer memory on which data has been prerecorded. Once data has been written onto a ROM chip, it cannot be removed and can only be read.

Unlike main memory (RAM), ROM retains its contents even when the computer is turned off. ROM is referred to as being nonvolatile, whereas RAM is volatile.

Most personal computers contain a small amount of ROM that stores critical programs such as the program that boots the computer. In addition, ROMs are used extensively in calculators and peripheral devices such as laser printers, whose fonts are often stored in ROMs.

In common usage, the term RAM is synonymous with main memory, the memory available to programs. For example, a computer with 8MB RAM has approximately 8 million bytes of memory that programs can use. In contrast, ROM (read-only memory) refers to special memory used to store programs that boot the computer and perform diagnostics. Most personal computers have a small amount of ROM (a few thousand bytes). In fact, both types of memory (ROM and RAM) allow random access. To be precise, therefore, RAM should be referred to as read/write RAM and ROM as read-only RAM.

Rgds

CU

Short for control unit, it is a typical component of the CPU that implements the microprocessor instruction set. It extracts instructions from memory and decodes and executes them, and sends the necessary signals to the ALU to perform the operation needed. Control Units are either hardwired (instruction register is hardwired to rest of the microprocessor) or micro-programmed.

ALU
Abbreviation of arithmetic logic unit, the part of a computer that performs all arithmetic computations, such as addition and multiplication, and all comparison operations. The ALU is one component of the CPU (central processing unit).



HARDWARE

Refers to objects that you can actually touch, like disks, disk drives, display screens, keyboards, printers, boards, and chips. In contrast, software is untouchable. Software exists as ideas, concepts, and symbols, but it has no substance.

Books provide a useful analogy. The pages and the ink are the hardware, while the words, sentences, paragraphs, and the overall meaning are the software. A computer without software is like a book full of blank pages -- you need software to make the computer useful just as you need words to make a book meaningful.

SOFTWARE
Computer instructions or data. Anything that can be stored electronically is software. The storage devices and display devices are hardware.

The terms software and hardware are used as both nouns and adjectives. For example, you can say: "The problem lies in the software," meaning that there is a problem with the program or data, not with the computer itself. You can also say: "It's a software problem."

PC

(1) Short for personal computer or IBM PC. The first personal computer produced by IBM was called the PC, and increasingly the term PC came to mean IBM or IBM-compatible personal computers, to the exclusion of other types of personal computers, such as Macintoshes.

In recent years, the term PC has become more and more difficult to pin down. In general, though, it applies to any personal computer based on an Intel microprocessor, or on an Intel-compatible microprocessor. For nearly every other component, including the operating system, there are several options, all of which fall under the rubric of PC .

MAINFRAME COMPUTER

A very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously. In the hierarchy that starts with a simple microprocessor (in watches, for example) at the bottom and moves to supercomputers at the top, mainframes are just below supercomputers. In some ways, mainframes are more powerful than supercomputers because they support more simultaneous programs. But supercomputers can execute a single program faster than a mainframe. The distinction between small mainframes and minicomputers is vague, depending really on how the manufacturer wants to market its machines.

A very good website for computer information.
http://http://www.webopedia.com/

rgds

EVERYDAY SCIENCE PAPER 1998


Note: Attempt TEN questions. All questions carry equal marks.

1. “Earthquakes have helped a great deal in deciphering the internal structure of the earth”. Comment on this statement.

2. Discuss briefly the achievements of Muslims in the development of science. State the reasons of downfall of science in Muslim Society.

3. Discuss in detail the fission and fusion processes. Which one of thee processes in the source of solar energy?

4. Give a detailed description of global warming and its possible effects on life. What measures have been taken by various nations to tackle this problem?

5. Give chemical name of one Nitrogenous and one Phosphorus containing fertilizer. What is the role of Nitrogen, Phosphorous and Potash in the growth and development of various parts of a plant.

6. Write short notes on the following:
(i) Conductor
(ii) Resistor
(iii) Semi-conductor
(iv) Thermistor
(v) Transistor

7. Write short notes on five of the following:
(i) Antibody
(ii) Blood group
(iii) Carbon cycle
(iv) Nitrogen cycle
(v) Scavenger
(vi) Reaction time
(vii) Photosynthesis
(viii) Starfish

8.Which of the following statements are true?
(i) Trout is a sea fish
(ii) Epiphytes is a plant that grows upon another plant.
(iii) Hepatitis is inflammation of membranes surrounding the brain.
(iv) Meningitis is the inflammation of liver.
(v) Equinox is the time when the sun appears vertically overhead at noon at the equator.
(vi) Drought is a long period of rain.
(vii) Joseph Aspdin is the inventor of cement.
(viii) Neurology is the science of nervous system.
(ix) Biochemistry is the application of statistics in the study of Biology.
(x) Aviculture is the science of the rearing of animals.

9. Name the quantities which are measured by the following units.
(i) Newton
(ii) Joule
(iii) Watt
(iv) Volt
(v) Light year
(vi) Angstrom
(vii) Acre-foot
(viii) Becquerel
(ix) Hertz
(x) Cusec

10. Match the cause of the disease:

DISEASE
CAUSE
Rickets
Plasmodium
Goiter
Protein deficiency
Typhoid
Iodine deficiency in diet
Merismis
Salmonella typhosa
Malaria
Deficiency of vitamin D

11. What is the function of each of the following in a motor car:
(i) Gear box
(ii) Battery
(iii) Carburetor
(iv) Dynamo
(v) Radiator

12. Explain the following
(i) Blood group
(ii) Short circuit
(iii) Short sight
(iv) International date line
(v) Plaster of Paris

13. Answer the following
(i) Of what lead pencils are made of?
(ii) Why is one’s breath visible in cold but not in hot weather?
(iii) What is the chemical composition of diamond?
(iv) Name the vaccine that protects against tuberculosis.
(v) Name the disease of the liver that causes a patient to turn yellow.

14. Fill in the blanks
(i) ___________ is a hypothetical region of space having a gravitational pull so great that no matter or radiation can escape from it.
(ii) ___________ are used against mould and fungi.
(iii) The science which deals with heredity is known as ___________.
(iv) Insulin is used for the treatment of ___________.
(v) ___________ is the first space man.
(vi) ___________ is the farthest planet from the sun in Solar System.
(vii) The distance between the earth and the sun is called ___________.
(viii) The study of chemical processes of living organisms is called ___________.
(ix) The first computer virus invented by two Pakistani brothers is called the ___________.
(x) Severe efficiency of vitamin C results in ___________.

15. Differentiate between any five of the following.
(i) Artery and vein
(ii) Hard water and soft water
(iii) E-mail and Snail mail
(iv) Apes and monkey
(v) Hydrostatics and hydrodynamics
(vi) Comet and meteor
(vii) Barrage and dam
(viii) Electron and hole
(ix) Isobars and isotopes
Autopsy and biopsy

rgds

8.Which of the following statements are true?
(i) Trout is a sea fish.F
(ii) Epiphytes is a plant that grows upon another plant.T
(iii) Hepatitis is inflammation of membranes surrounding the brain.F
(iv) Meningitis is the inflammation of liver.F
(v) Equinox is the time when the sun appears vertically overhead at noon at the equator.T
(vi) Drought is a long period of rain.F
(vii) Joseph Aspdin is the inventor of cement.T
(viii) Neurology is the science of nervous system.T
(ix) Biochemistry is the application of statistics in the study of Biology.T
(x) Aviculture is the science of the rearing of animals.F


9. Name the quantities which are measured by the following units.
(i) Newton-Force
(ii) Joule-Work Energy
(iii) Watt-power of electricity
(iv) Volt-potential difference
(v) Light year-distance of stars and planets
(vi) Angstrom-length
(vii) Acre-foot -volume
(viii) Becquerel -radioactivity
(ix) Hertz--frequency
(x) Cusec-rate of flow of water



10. Match the cause of the disease:


Rickets ----deficiency of vit D
Plasmodium ---Malaria
Goiter---iodine deficiency
Typhoid--- Salmonella typhosa
Merismis ---protein deficiency





14. Fill in the blanks
(i) __black hole_________ is a hypothetical region of space having a gravitational pull so great that no matter or radiation can escape from it.
(ii) ___fungicides________ are used against mould and fungi.
(iii) The science which deals with heredity is known as __genetics_________.
(iv) Insulin is used for the treatment of __diabetes_________.
(v) __Yuri Gagarin_________ is the first space man.
(vi) ___pluto________ is the farthest planet from the sun in Solar System.
(vii) The distance between the earth and the sun is called __Astronomoical unit_________.
(viii) The study of chemical processes of living organisms is called _biochemistry__________.
(ix) The first computer virus invented by two Pakistani brothers is called the ____Brain_______.
(x) Severe efficiency of vitamin C results in ___Scurvy________.



Correct where wrong

12. Explain the following

(i) Blood group

A blood type (also called a blood group) is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins or glycolipids, depending on the blood group system, and some of these antigens are also present on the surface of other types of cells of various tissues. Several of these red blood cell surface antigens, that stem from one allele (or very closely linked genes), collectively form a blood group system.

(ii) Short circuit

1
an electrical circuit of lower than usual resistance, especially one formed unintentionally.

2
A short circuit (sometimes abbreviated to short or s/c) allows a charge to flow along a different path from the one intended. The electrical opposite of a short circuit is an open circuit, which is infinite resistance between two nodes. It is common to misuse "short circuit" to describe any electrical malfunction, regardless of the actual problem.

(iii) Short sight
the inability to see things clearly unless they are relatively close to the eyes; myopia.

Detail:
short-sightedness, is a refractive defect of the eye in which collimated light produces image focus in front of the retina when accommodation is relaxed.

Those with myopia see nearby objects clearly but distant objects appear blurred. With myopia, the eyeball is too long, or the cornea is too steep, so images are focused in the vitreous inside the eye rather than on the retina at the back of the eye. The opposite defect of myopia is hyperopia or "farsightedness" or "long-sightedness" — this is where the cornea is too flat or the eye is too short.

(iv) International date line
longitude line located at 180 degrees, longitude line that divides time zones so that one side is one one calendar day and the other side is on the next calendar day

(v) Plaster of Paris
Plaster of Paris, or simply plaster, is a type of building material based on calcium sulfate hemihydrate, nominally CaSO4·0.5H2O. It is created by heating gypsum to about 150 °C.

15. Differentiate between any five of the following.

(i) Artery and vein

Arteries
muscular blood vessels that carry blood away from the heart. All arteries, with the exception of the pulmonary and umbilical arteries, carry oxygenated blood.

Vein
a blood vessel that carries blood toward the heart. The majority of veins in the body carry low-oxygen blood from the tissues back to the heart; the exceptions being the pulmonary and umbilical veins which both carry oxygenated blood.

(ii) Hard water and soft water

Hard water
water that has a high mineral content (contrast with soft water), usually consisting of calcium (Ca2+) and magnesium (Mg2+) ions, and possibly including other dissolved metals, bicarbonates, and sulfates. Calcium usually enters the water as either calcium carbonate (CaCO3) in the form of limestone and chalk, or calcium sulfate (CaSO4) in the form of other mineral deposits. The predominant source of magnesium is dolomite (CaMg(CO3)2). Hard water is generally not harmful.

Soft water
the term used to describe types of water that contain few or no calcium or magnesium ions. The term is usually relative to hard water, which does contain significant amounts of such ions.

(iii) E-mail and Snail mail

E-Mail
method of correspondence via the Internet; communication sent by electronic mail

Snail Mail
regular mail, normal postal service (not electronic mail)

(iv) Apes and monkey

A monkey is any member of either the New World monkeys or Old World monkeys, two of the three groupings of simian primates, the third group being the apes.

Detail :
The New World monkeys are classified within the parvorder Platyrrhini, whereas the Old World monkeys (superfamily Cercopithecoidea) form part of the parvorder Catarrhini, which also includes the apes. Thus, scientifically speaking, monkeys do not form a "natural group", in that the Old World monkeys are actually more closely related to the apes than they are to the New World species.

There are 264 known extant species of monkey. Because of their similarity to monkeys, apes such as chimpanzees and gibbons are often called monkeys in informal usage, though they are not monkeys. Conversely, due to its size (up to 1 m) the Mandrill is often thought to be an ape, but it is actually an Old World monkey. Also, a few monkey species have the word "ape" in their common name. Because they are not a single coherent group, monkeys do not have any particular traits that they all share and are not shared with the remaining group of simians, the apes.


(v) Hydrostatics and hydrodynamics

Hydrostatics
Fluid statics (also called hydrostatics) is the science of fluids at rest, and is a sub-field within fluid mechanics

Hydrodynamics
the branch of science concerned with forces acting on or exerted by fluids (especially liquids).

(vi) Comet and meteor

Comet
Any icy object that exists within the solar system. They are pieces of the primitive, unprocessed matter that formed the solar system 4.6 x 109 years ago. They are typically a few kilometres across and consist mainly of dust grains, frozen water, carbon monoxide and carbon dioxide; they contain many simple organic molecules.

Meteor
A meteoroid is a small sand to boulder-sized particle of debris in the Solar system. The visible path of a meteoroid that enters Earth's (or another body's) atmosphere is a meteor, commonly called a "shooting star" or "falling star". Many meteors are part of a meteor shower.

(vii) Barrage and dam

Barrage
Not built at heights
Pressure is not enough to produce electricity
Only Canals are marked out of it

Dam
Built at heights
Pressure is enough to move turbines so hydroelectricity is generated

(Kindly Correct or Improve)

(viii) Electron and hole

Electron
They belong to the lepton family and are the negatively charged components of atoms (1.6 x10^-19 coulomb). In the simplest model of the atom, electrons are envisaged to move around the atomic nucleus in specified circular and elliptical orbits.

Electron Hole
An electron hole is the conceptual and mathematical opposite of an electron, useful in the study of physics and chemistry. The concept describes the lack of an electron. It is different from the positron, which is the antimatter duplicate of the electron.

(ix) Isobars and isotopes

Isobars
line on a weather map or chart that connects areas of equal barometric pressure

Isotopes
Any of the several different forms of an element each having different atomic mass (mass number). Isotopes of an element have nuclei with the same number of protons (the same atomic number) but different numbers of neutrons.

(x)Autopsy and biopsy

Autopsy
postmortem, examination of a corpse to determine cause of death

biopsy
removal and study of a tissue sample for diagnostic purposes

__________________
When you have to shoot, shoot. Don't talk. ~ The Good, The Bad, and the Ugly

In my previous post I defined Isobars as "a line on a weather map or chart that connects areas of equal barometric pressure". This definition was from Meteorology. The examiner however, would be expecting the difference on the basis of Nuclear Physics given as below

Isotopes and Isobars

The various nuclides, or species, of a particular chemical element with equal proton number (atomic number), but different neutron numbers were called isotopes of the element, before the more inclusive term "nuclide" was internationally accepted (ca. 1950. Such particular nuclides may still be called "isotopes." However, nuclides with equal mass number but different atomic number are called isobars (isobar = equal in weight), whereas Isotones are nuclides of equal neutron number but different proton numbers.

Reference

__________________
When you have to shoot, shoot. Don't talk. ~ The Good, The Bad, and the Ugly

Respected members are requested to answer the following question:

Q: Feed back mechanism of Human System (Paper 2002)

Q: Why an object weight is less at the equator than at poles (Paper 2007)

Thanks

Best Regards...

This question is ambiguous. I could not find it in 2002 EDS paper as well. Kindly re-check

The strength (or apparent strength) of Earth's gravity varies with latitude, altitude, and local topography and geology. A simple answer to this question is that this difference in weight occurs mainly due to two reasons

1 - Rotation velocity of the earth (and, thus, centripetal force) decreases as one moves towards the poles local gravity, g, increases from 9.789 m·s^−2 at the equator to 9.832 m·s^−2 at the poles

2 - the equatorial bulge and the effects of centrifugal force mean that sea-level gravitational acceleration increases from about 9.780 m·s^-2 at the equator to about 9.832 m·s^-2 at the poles

This causes an object to weigh about 0.5% more at the poles than at the equator.

For a detailed answer to this question please click here and read the article under the heading "Variations on Earth"



Regards

__________________
When you have to shoot, shoot. Don't talk. ~ The Good, The Bad, and the Ugly

Thanks for your prompt response.....

Sorry, it was a mistake... you can find it in Paper 2000 EDS

Q#3 (a) Feed back mechannism of human system


Best Regards....