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Old Friday, May 15, 2009
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Default Eds - 1997


Every Day Science Paper - 1997
Partial Solution




Note: Attempt TEN questions. All questions carry equal marks. Draw diagrams where necessary. Negative marking would be done for incorrect answers in Question Nos. 13 and 14.

1. Discuss the role and achievements of Muslim physicists during the 10th century.

2. Explain the structure of Earth and its atmosphere.

3. Write short notes on any two of the following:

(i) Solar eclipse
(ii) Thermoplastics
(iii) Non-renewable energy resources.

4. What are pesticides? Discuss their classification, commonly in use with agronomists.


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

Answers:

(i) BIT and BYTE:

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).


(ii) RAM and ROM:

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.


(iii) C.U. and A.L.U:

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).


(iv) Hardware and Software:

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."


(v) Personal computer and mainframe:

Personal Computer (PC):

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.


6. Explain any five of the following terms (in not more than four lines each):

(i) Osmosis Glycolysis
(ii) Phototaxis
(iii) Transpiration
(iv) Saponification
(v) Emulsion

Answers:

(i) Osmosis:

osmosis, in botany and chemistry, the flow of one constituent of a solution through a membrane while the other constituents are blocked and unable to pass through the (selecyively permeable membrane)membrane. experimentation is necessary to determine which membranes permit selective flow, or osmosis, because not all membranes act in this way. many membranes allow all or none of the constituents of a solution to pass through; only a few allow a selective flow.


Glycolysis:

Glycolysis, chemical process in which glucose is broken down, or catabolized, into the simpler sugar lactic acid, and energy is released.


(ii) Phototaxis:

movement of organism caused by light: movement of an organism either toward or away from a source of light . Phototaxis is called positive if the movement is in the direction of light and negative if the direction is opposite.


(iii) Transpiration:

Transpiration, evaporation of water particles from plant surfaces, especially from the surface openings, or stomata, on leaves . Stomatal transpiration accounts for most of the water loss by a plant, but some direct evaporation also takes place through the surfaces of the epidermal cells of the leaves.


(iv) Saponification:

Saponification is the hydrolysis of an ester under basic conditions to form an alcohol and the salt of a carboxylic acid (carboxylates). Saponification is commonly used to refer to the reaction of a metallic alkali (base) with a fat or oil to form soap. Saponifiable substances are those that can be converted into soap.

Sodium hydroxide (NaOH) is a caustic base. If NaOH is used a hard soap is formed, whereas when potassium hydroxide (KOH) is used, a soft soap is formed. Vegetable oils and animal fats are fatty esters in the form of triglycerides. The alkali breaks the ester bond and releases the fatty acid salt and glycerol. If necessary, soaps may be precipitated by salting it out with saturated sodium chloride. The saponification value is the amount of base required to saponify a fat sample.



(v) Emulsion:

A suspension of small globules of one liquid in a second liquid with which the first will not mix: an emulsion of oil in vinegar


7. Fill in the blanks:

(i) A sheet of muscles called diaphragm separates the chest from the abdomen.

(ii) In the human body, blood-clotting factor is produced by the liver.

(iii) Human blood is able to carry large amounts of oxygen because of the chemical hemoglobin.

(iv) The living part of a plant cell is composed of a nucleus and cytoplasm.

(v) The pattern for building protein molecules is stored in the messenger RNA.

(vi) Anvil and stirrup are names of bones present in the ear.

(vii) The front of the eye is covered with a tough transparent material called cornea.

(viii) The young plant inside a grain of wheat is called the embryo plant.

(ix) In born behaviour that involve only one part of the body are called reflex action.

(x) The smallest branches of an artery lead into tiny blood vessels called capillaries.


8. What are Exocrine glands? Give names of any four along with the name of their secretion.

Answer:

Glands are of two principal types:

(1) those of internal secretion, called endocrine, and
(2) those of external secretion, called exocrine.

Some glands such as the pancreas produce both internal and external secretions. Because endocrine glands produce and release hormones directly into the bloodstream without passing through a canal, they are called ductless. For the functions and diseases of endocrine glands, see Endocrine System.

Sweat gland..............Sweat
Sebaceous gland........Sebum
Lacrimal gland ...........Tears
Salivary gland.............Saliva


9. Which quantity do the following units measure:

(i) Volt
(ii) Coulomb
(iii) Walt
(iv) Ohm
(v) Mho
(vi) Ampere
(vii) Dyne
(viii) Celsius
(ix) Joule
(x) Calorie

Answers:

(i) Voltage
(ii) Charge of Electricity
(iii) Power
(iv) Resistance
(v) Conductivity
(vi) Current
(vii) Force
(viii) Temperature
(ix) Energy
(x) Heat


10. Give scientific reasons (in not more than four lines each) for the following:

(i) Meat takes longer to cook on the mountains
(ii) Water remains cool in earthen pitchers
(iii) Ice and salt mixture is used as a freezing agent by manual ice cream makers.
(iv) It is not advisable to sleep under trees during the night.
(v) Greenhouse operators paint their glass roofs white in summer.

Answers:

(i) Meat takes longer to cook on the mountains:

The atmospheric pressure decreases as the altitude increases. The boiling point of water is 100 c at standard atmospheric pressure. At the mountains this atmospheric pressure is less, thus water boils at temperature lower than 100c.Therefore the meat takes longer time to be cooked. This can be overcome by using pressure cookers.


(ii) Water remains cool in earthen pitchers:

The water gets evaporated through the pores of earthen pot and in so doing takes more heat from the water in the form of latent heat and gets cooled in turn. While a metal or glass container has no pores and therefore does not permit the evaporation of water which does not get so cooled.


(iii) Ice and salt mixture is used as a freezing agent by manual ice cream makers.

Salt lowers down the temperature of ice by decreasing its freezing point. That is why ice and salt mixture is used as freezing agent in ice cream making.


(iv) It is not advisable to sleep under trees during the night.

Because plants at night releases carbon dioxide and takes up oxygen.


(v) Greenhouse operators paint their glass roofs white in summer.

In summer there is already much hot and white colour has a property of reflection of light to a maximum. And therefore white colour is painted on the roofs in the summer.


11. Which part/organ of the human body do the following belong:

(i) Eustachian tube
(ii) Cartilage
(iii) Auricle
(iv) Tendon
(v) Dendrites

Answers:

(i) Eustachian tube...... Ear
(ii) Cartilage............... Connective tissue
(iii) Auricle................. Ear
(iv) Tendon ................Muscle
(v) Dendrites.............. Neuron


12.Briefly describe the solar system. Name its members outlines the main characteristics of any two members.


13. Fill in the blanks.

(i) Insulin is produced in the human body by the ___________. (Liver, Pancreas, Gallbladder)

(ii) In an animal cell protein is synthesized in the ___________. (Nucleus, Mitochondria, Ribosome)

(iii) Chemically finger nails are made up of ___________. (Carbohydrate, Protein, Minerals)

(iv) Muscle stiffness is a symptom caused by the disease ___________ (Polio, Tetanus, Rabies)

(v) Animals which obtain their food from dead organisms are called ___________. (Carnivores, Scavengers, Saprophytes)

(vi) ___________ is not affected by cooking. (Ascorbic acid, Thiamin, Riboflavin)

(vii) Rickets is caused by the deficiency of vitamin ___________. (A, D, K)

(viii) The number of chromosomes in the spermatozoa is ___________ (Twenty-two,twenty-three, Forty-six)

(ix) The fat in our food is digested by the enzymes ___________. (lipase, lactase, trypsin)

(x) The most abundant element in the human body is ___________. (Carbon, Hydrogen,Oxygen)


14. Which of the following statements are false and which are true.

(i) Sound is a form of energy.
True

(ii) A fraction of sunlight is refracted as it enters the earth’s atmosphere.
True

(iii) The energy possessed by a water fall is kinetic energy.
False

(iv) Rainbows are produced by the reflection of light through raindrops.
False

(v) Light switches in our homes are connected in parallel series.
True

(vi) Generators convert mechanical energy into electricity.
True

(vii) Modern incandescent bulbs contain filaments made of copper.
False

(viii) A steam engine cannot be powered by fossil fuels.
False

(ix) Nuclear energy is a cheap source of abundant electricity.
True

(x) Oil burns cleaner and is less damaging to the environment than coal as a fuel.
True


15. Match words of List A with those of List B.

...A.....................B

Protein.....................Fat
Magnesium................Milk
Carotene..................Ozone
Bauxite....................Nitrogen
Haemitite.................Amino acid
Casein.....................Vitamin A
Pancreas.................Aluminium
Quartz....................Chlorophyll
Chlorofluorocarbon....Iron
Urea......................Silicon

Answers:

...A..............................B

Protein.....................Amino acid
Magnesium................Chlorophyll
Carotene..................Vitamin A
Bauxite....................Aluminium
Haemitite.................Iron
Casein.....................Milk
Pancreas.................FATS
Quartz....................Silicon
Chlorofluorocarbon....Ozone
Urea.......................Nitrogen


~~~~~~~~~******~~~~~~~~~
__________________
No matter how fast i run or how far i go it wont escape me, pain, misery, emptiness.

Last edited by Xeric; Monday, May 25, 2009 at 02:01 PM.
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