General Science Solved Past Paper 9th Class 2015 Karachi Board

SECTION “A” (COMPULSORY)(M.C.Q.S) 

1. Choose the correct answer for each from the given options

  1. Science is not:
    * Exploration
    * Experimentation
    * Testing
    * Traditions
  2. A nation is said to be strong on the bases of its:
    * Manpower
    * Natural resources
    * Science and Technology
    * Economic well being
  3. The most essential element in petroleum and other organic compounds is:
    * Calcium
    * Sulpher
    * Magnesium
    * Carbon
  4. Which one is not an organic food?
    * Proteins
    * Carbohydrates
    * Lipids
    * minerals
  5. Best food means:
    * Well cooked food
    * Rich food
    * Simple food
    * Balanced food
  6. Which food represents a balanced diet?
    * Fish
    * Apple
    * Eggs
    * Milk
  7. Influenza is caused by:
    * Air
    * drinking water
    * Mosquitoes
    * Shaking hands
  8. A type of psychosis is:
    * Schizophrenia
    * Anxiety
    * Hysteria
    * Depression
  9. Percentage of Nitrogen in urea is:
    * 36%
    * 51%
    * 46%
    * 42%
  10. Ozone layer is thinning by the discharge in the atmosphere of:
    * CO
    * S02
    * NH3
    * Chloro flouro carbon gases
  11. The energy that we get by eating food is known as:
    * Mechanical energy
    * Potential energy
    * Kinetic energy
    * Heat energy
  12. Solar energy is also known:
    * Radiant energy
    * Thermal energy
    * Mechanical energy
    * Chemical energy
  13. The substance used as medium between the two plates of a capacitor is known as:
    * Conductor
    * Semi Conductor
    * Dielectric
    * Electrolyte
  14. Which one is connected in series with the live wire in the electric circuit of house?
    * Galvanometer
    * Voltmeter
    * Fuse
    * Ammeter
  15. The commercial unit of electric energy is:
    * Ohm
    * Volt
    * Farad
    * Kilo-watt hour
  16.  During which country many advances were made in different fields of science:
    * 17th
    * 18th
    * 19th
    * 20th
  17. X-rays were discovered in the year:
    * 1859 A.D.
    * 1895 A.D.
    * 1896 A.D.
    * 1869 A.D.
  18. PCSIRwas set up in:
    * 1952
    * 1954
    * 1962
    * 1964
  19. The Central Office of Suparco in Pakistan is situated at:
    * Karachi
    * Lahore
    * Islamabad
    * Peshawar
  20. Artificial satellite revolves in the gravitational field of:
    * Sun
    * Earth
    * Mercury
    * Venus

SECTION “B” (SHORT-ANSWER QUESTIONS)

NOTE: Answer 10 questions from this section.
2. Describe the limitations of science

ANSWER:

(i) Due to development and advancement of science and modern instrument environmental problems are created.
(ii) Growth of industries caused pollution of air, water and soil.
(iii) It is feared that due to vast use of resources e.g petroleum and nature gas no more resources will be left for continuously of modern civilization.
(iv) As science has nothing to do with religion and spiritual values wrong use of scientific technology is being done now-e-days.
(v) Though internet and computer has brought great advancement in progress, the character and moral values have due to its misuse for films etc.

3. Name any 10 organic compounds, used in daily life.

ANSWER:

Organic compound, used in daily life are:
(i) Vinegar (ii) Fats (iii) Carbohydrates (iv) Petroleum (v) Rubber (vi) Plastic (vii) Soap (viii) Nylon (ix) Dyes (x) Detergents

4. Write how vaccines have been saving the lives of million?

ANSWER:

Vaccines: Vaccines provide protection against a number of diseases like small pox, poliomyelitis, T.B, Tetanus and many others.

A vaccine is actually a few germs of that same diseases from which protection is required. When injected to a healthy child or even a grown up person, the vaccine enters the blood steam. This awakens the action of white blood corpuscles against that disease. The immunity against that disease increases fully. Any actual attack of that disease does not make the person sick because there is already protection in the body

Small pox: Small pox has been almost eradicated from all parts of world by vaccination. Pakistan has also been declared a free zone against small pox:

Polio: Polio can be prevented by vaccine for poliomyelitis; the vaccine is given to child under every five years of age. Tuberculosis: Tuberculosis has been prevented for millions by BCGvaccine. Whooping

Cough: Whooping Cough has been eradicated and prevented by DPT vaccine given in early months of a baby is life.

Typhoid: Typhoid has been prevented and cured by a capsule of oval vaccine for millions of people.

Tetanus: Tetanus has also been prevented to spread by DPTvaccine for thousands and thousands of people.

Cholera: Cholera can be avoided by tetracycline and the vaccine for cholera.

When a child is born a full course of vaccine for different diseases in administered at different ages in the early period. This course of vaccines provides protection to the growing child in his life.

5. Explain what a balanced diet is. 

ANSWER:

A balanced diet in that which consists of food that will give carbohydrates, proteins, fats, vitamins, and minerals and off course water to human body, all in right quantities.

Different people need different amounts of energy. However there is a simple dietary plan useful to most people.

(1) MILK: One pint or more a day.
(2) EGGS: One or more a day
(3) MEAT, CHEESE: One serving a day, fish or poultry.
(4) VEGETABLES & FRUITS: Green and yellow vegetables one serving a day is desirable.
(5) CITRUSFRUITS: (Orange, grape fruit) one whole or in juice.
(6) CEREALS & BREAD: Bread specially from unsaved flour (six slices with butter)
(7) WATER: At least six to eight glasses a day on moderate weather days but more on hot days. If you take these foods, you have no starvation symptoms what so ever on three meals a day.

6. God has gifted human beings with many defense systems. Discuss. 

ANSWER:

God has gifted human beings with many defense systems against diseases these can be:
(i) Immunity in the body.
(ii) Healthy habits.
(iii) Brain to think and decide what is beneficial and what is harmful. Spinal cord protects from sudden harms to body by involuntary actions.
(iv) Excreting system to discard unwanted products from the body.
(v) Circulatory system to distribute food we eat to all parts and cells of the body
(vi) “Respiratory system to give oxygen to all living beings.

7. Why is snow present usually on the top of mountains and absent at their bottom? 

ANSWER:

Temperature affects the atmosphere and climate. The atmosphere absorbs heat or the solar energy of the sun lesser than the earth below, which is solid. Hence the temperature is low in the upper layers of air, than near earth. Therefore, snow remains as it is on mountain tops; while higher temperature near earth surface melts the snow.

8. What do you understand by a chain reaction? 

ANSWER:

NUCLEAR FISSION REACTION:
The splitting of a heavy radio active nucleus into fragments with the emission of energy when bombarded by a neutron is called Fission. EQUATION OF FISSION:

EQUATION OF FISSION

EQUATION OF FISSION

The energy released is due to the fact that, when a nucleus splits into fragments, the total mass of the fragments is less than that of the nucleus . This mass difference according to Einstein’s mass energy relation appears as energy.

CHAIN REACTION:
In a fission reaction each nucleus emits about two to three neutrons. These neutrons collide with the other uranium nuclei and cause fission in them. The nuclei which undergo a fission reaction will emit neutrons. These neutrons will produce further fission in other nuclei. This process continues, more and more neutrons are produced and a larger amount of energy is released. This is called a nuclear chain reaction. 

9. State and explain Ohm’s law.

ANSWER:

OHM’S LAW:
A German Physicist George Simon Ohm who discovered the “the current passing through a conductor is directly proportional to the potential difference applied across its ends, provided the temperature and other physical condition of the conductor are kept constant”. This statement is referred to as Ohms Law.

10. What are semiconducting substances?

ANSWER:  

Semi-Conducting Substances:

A semi-conductor is an element which can conduct electricity to a very small extent. Example Silicon and Germanium

This is so because all the four valiancy electrons of each atom form, covalent bonds with their neighboring atoms, since these electrons are tightly held in covalent bonds there are no really free electrons to form an electric current.Electric current is actually the flow of electrons through a wire. As this cannot take place easily silicon and germanium are called semi-conductors.

Their electrical conductivity can be increased by adding a small amount of element which has 3 or 5 valence electrons in its atoms this is called Doping.

11. Describe the importance of sugar industry?

ANSWER:

SUGAR INDUSTRY:

Sugar is used to sweeten the food. In nature it is synthesized and stored in all plants as a part of their food.

Sugar industry has made a tremendous progress and the number of sugar factories gave increased to 78 as against 9 at the time of partition. Sugar industry is scattered over N.W.F.P,Punjab 40 and Sindh 32. It is however, concentrated in the sugarcane growing areas because sugarcane cannot be conveniently transported over longer distances as compared to other raw materials. The sugar industry has an installed capacity of 5.0 million tones production. Although most of the sugar industry in Pakistan uses sugarcane as raw material, yet some mills in N.W.F.P. use sugar beat as well for one or two months when sugar cane is exhausted.

12. What do you about optical fiber system?

ANSWER:

OPTICALFIBERSYSTEM:

It is a means of communication messages and information can be sent to all places very quickly using laser beams, through optical fibers.

OPTICALFIBERSYSTEM

OPTICALFIBERSYSTEM

In an optical fiber the light can travel with little loss because the light in totally reflected whenever it strikes the core-cladding interface.

In developed countries, optical fibers are used to carry telephone signals and other modern communication systems using laser beams. A single strand of light carrying fiber can carry several thousand telephone messages simultaneously without interfering with each other. Optical fibers are very light in weight, more flexible and much cheaper than copper cables. A bundle of 30 fibers are often used to from a cable. The information carrying capacity of light is thousand times greater than that of electricity or radio waves.

13. Write down the misuses and disadvantages of nuclear energy.

ANSWER:

Disadvantages of Nuclear Energy:

Nuclear energy contains radioactivity rays and these rays have very harmful effects.
(i) When these rays enter our body they destroy body cells, decrease red blood corpuscles and causes many diseases.
(ii) The temperature rises to many million degrees and kills all life on earth.
(iii) It causes cataract of eyes.

Misuse of Nuclear Energy:
(i) Atom bombs and others Nuclear weapons have been made by Nuclear Energy.
(ii) Due to such atomic weapons the world is under a constant threat of war and destruction.

14. What do you know about SPARCO?

ANSWER:

PAKISTAN’S SPACE PROGRAM:

Space exploration yields useful information and provides useful economic benefits

Pakistan is one of the very few developing countries which has established an organization for space research. The name of this organization is SUPARCO.It stands for space and upper atmosphere research corporation. This organization has its research and testing facilities at Sonmiani near Karachi. It has fired several rockets for weather research. It has also established ground stations to receive data from weather satellites round the clock, for short and long range weather forecasts

15. Describe ’tile first aid for heart attack.

ANSWER:

FIRST AID FOR HEART ATTACK:

(i) Lay the victim on the floor or on a bed. Elevate his head and shoulders on a pillow 0 folded blanket.
(ii) Keep him absolutely quiet.
(iii) Do not move the victim until the pains has eased. Mean while cover him as necessary to keep him warm.
(iv) If the person has had previous similar attacks, he may be carrying nitroglycerin tablets. If so, one of these should be placed under his tongue. This will usually terminate the attack promptly. This medication is best administered with the patient lying down, as it may cause fainting.
(v) Arrange for him to see his doctor as soon as possible.

16. What is neurosis and psychosis? Describe their causes. 

ANSWER:

NEUROSIS:

It is an illness resulting from some sort of psychological conflicts. It involves stimulation of autonomous nervous system and affects a portion of mental functioning. REASON: Neurosis may appear due to anxiety hysteria, phobia or simply by depressions of any kind.

PSYCHOSIS:

It is a major mental disorder in which a person’s ability to think and respond emotionally is so seriously impaired that he i~ unable to meet the ordinary demands of life. It involves hallucinations, delusions, schizophrenia and melancholia.
REASON: These mental disorders may appear due to aging, or endocrinal, metabolic and nutritional disorder or infections or intoxication or fear etc. The mental illnesses may result into drug abuse or might have resulted from the drug abuse.

SECTION ‘C’ (DETAILED-ANSWER QUESTIONS)(30) 

Note: Attempt 3 questions from this Section.
17. What are Enzymes? Write their properties and their types in detail. 

ANSWER:

Enzymes: These are complex chemical compounds which help to digest the different components of food we eat. Classification: Enzymes are divided into three groups.
(i) Amylolytic enzyme : They digest carbohydrates.
(ii) Proteolytic: Which digest proteins.
(iii) Lipolytic: Which break the fats

18. Describe as to how does prayer contribute to good health? 

ANSWER:

Prayer——–a good exercise:

Offering prayer five times a day by Muslims is of immense value spiritually, morally and physically. On one hand offering prayer teaches to be highly disciplined, neat and clean and has a great hygienic value

Prayer involves the exercise of muscles, nerves, tissues, bones, joints and stomach. While offering prayer standing (Qiyam) provides exercise for muscles and bones and helps to keep the body in right vertical straight posture. While going for Ruku, one bends the body at exactly a right angle. While going back in the erect position (Qoma) again the joints of the waste get movement along with muscles. Going in Sajda involves movements of muscles, nerves, joints, eyes and head. In Sajda the brain and facial parts of the body get enough blood and enough oxygen. Thus the brain also gets fresh blood and oxygen. Ultimately all the parts of the body are moved and get adequate amount of blood. As such they get enough oxygen and enough energy. So by offering prayer five times a day one improves his circulatory, respiratory systems as well. Thus prayer is source of good health and hygiene.

19. What is smoking? What are its impacts on health of a smoker in particular and on society in general? 

ANSWER:

SMOKING:
Smoking is inhaling the fumes of tobacco by lighting cigarettes, cigars, huqqa etc. Smoking is injurious to health. It causes many direct or indirect diseases

EFFECTS:
Tobacco smoke contains about 1000 chemicals which are harmful. One of these chemical in nicotine which is a colourless drug and people get addicted to it though it is a poison. The main effect of nicotine is on arteries which are blood carrying tubes. Arteries become narrow by nicotine so heart has to work harder to keep the blood supply normal. A smoker more susceptible to heart attacks

Tar is a brown sticky substance which accumulates in smokers lungs and contains many cancer inducing chemicals. Carbon mono-oxide present in smoke of cigarettes reduces the potential of oxygen absorption of blood. Many other gases like hydrogen-ammonia-cyanide and butane present in the smoke irritate the lungs air passages causing them to produce mucus.

Harmful effects of smoking on society:
(i) When the smoke spreads the people near the smoker are also affected equally by the chemicals spread in air.
(ii) Carbon monoxide given out in smoke is also inhaled by others and it effects the oxygen absorption of blood.
(iii) Others gases like hydrogen-ammonia-cyanide and butane irritate the lung air passage of the people around the smoke.
(iv) Smoking causes pollution of air also and the atmosphere of the room becomes full of the smell of tobacco smoke.
This may also causes suffocation if the room is closed.

20. Differentiate between climate and weather. Name the factors responsible for climate changes. 

ANSWER:

WEATHER: It is the condition of atmosphere regarding pressure temperature wind, humidity and rainfall of a place for a short period of time.
CLIMATE: Climate refers to the average weather contiition of a region over a long period of time, which can be throughout the season.

FACTOR RESPONSIBLE FOR CLIMATE CHANGES:
Climate of a region depends on the interaction of many factors like air pressure, temperature, humidity and wind.
AIR PRESSURE: Air is made up of tiny molecules. Due to their movement they spread outward and upward but due to the gravitational pull, the air pressure is higher near the earth’s surface. It gradually decreases away from earth.
TEMPERATURE: Temperature is the degree of hotness of a body. The atmosphere absorbs some of the sun’s energy but much more is absorbed by the earth. The earth then radiates the energy back. This is the energy you feel coming out of warm sand or a hot road. The regions around equator receive straight hot sun rays more than the areas towards the poles.
WIND: Air moves from higher pressure to low pressure and its speed depends on the difference in pressure. Wind blows from equator to the poles and from poles to the equator. Huge wind belts blowing across the earth alter the temperature, cause the rainfall and hence play an important role in determining the climate of an area.
HUMIDITY: It is the amount of water vapours present in the air. It comes from evaporation of water from the oceans. The humidity depends on temperature. Warm air can hold more moisture than the cold air.

21. Describe some methods by which we can conserve energy

ANSWER:

CONSERVATION OF ENERGY: Our energy sources in Pakistan are limited. We have nothing surplus to save for the future use. Our demand of energy is much greater than its supply.

By conservation of energy we mean that whatever energy sources we have at hand, they must be used very carefully without any waste.
(i) We light on more bulbs unnecessarily. Only five percent of the electrical energy is changed into light in ordinary filament bulbs. On the other hand, the fluorescent lamp (commonly know as tube light rod) uses less current to give the same amount of tight that ordinary bulbs do. It is advisable fo use fluorescent lamps instead of an incandescent bulbs.
(ii) Old vehicles and transportations trucks consume more fuel than the new ones. These vehicles also cause great amount of air pollution. Such vehicles may not be allowed to be used any further.
(iii) Natural gas is used in homes for domestic purpose and is also used in fertilizer industry. We should also use the natural gas very wisely. It should not be left burning in stoves and other appliances like gas heaters, and gas lamps unnecessarily.
(iv) If we use these energy sources recklessly, we will soon run short of these sources and we will be soon under energy crises. The result will be less production in industries and less national progress.

Posted on December 12, 2015 in 9th Class 2015 Karachi Board Past Papers

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