Q. 2. (a is subjective)

(b)
(i) Name two minerals which are exported from Pakistan.
Silica Sand (Glass Industry)
Gypsum (Cement)
Salt

(ii) Name some gem-minerals used in Jewellery.
Topaz
Ruby
Emerald
Quartz
Diamond
Sapphire

(iii) What is dead sea.
The Dead Sea, also called the Salt Sea, is a salt lake bordering Jordan to the east and Israel to the west. It is 427 metres below sea level thus the lowest point of earth's elevation. Moreover due to its high density, one cannot drown in this lake.

(iv) Why does the Sun appears orange-red at the time of Sunrise and Sunset.
The sun appears red because the atmosphere scatters blue light more efficiently. Since the sunlight has to travel through significantly more atmosphere when it is on the horizon (due to the angles involved), much more of the blue (and green and purple) light gets scattered and redirected in a random direction that is not toward you. But the red light gets scattered less, so the red light makes it from the sun to your eye. Since there is more red light, the sun looks red.

(v) Why does the total Eclipse can happen only at the new Moon.
Since Eclipse is a condition when sun, earth and moon are col-linear, which is possible only when we have a new moon which makes the path of the 3 objects col-linear.

Q. 3. (a) Name popular forms of Energy. Write five various scientific devices used to convert one type of energy into another form of energy.
Forms: Solar, Light, sound, Mechanical (Potential and Kinetic), Chemical, Thermal (Heat) and Nuclear Energy.
Devices: Generator, Microphone, Speaker, Vaccumtube, Bulb, Dynamo, Battery, Photo-diode

b) Write meaning of the following units:
(i) Barrel: 164 Litres UK, US 119 Litres
(ii) Joule: equal to the work done by a force of one newton when its point of application moves one metre in the direction of action of the force
(iii) Btu: he amount of heat needed to raise 1 lb of water at maximum density through one degree Fahrenheit, equivalent to 1.055 × 103 joules
(iv) KWh: Unit of electricity consumption when one uses 1kw energy for one hour.
(v) Newton: the force that would give a mass of one kilogram an acceleration of one metre per second per second

Q. 8. Explain the scientific reasons for the following:
(i) It is not advisable to sleep under trees during the night.
They release CO2 which is harmful for humans.

(ii) Water boils quicker on mountains. Due to lesser pressure and thus lesser boiling point.

(iii) Rainbow is produced in the sky after rain fall and sunlight. Due to dispersion of light which are present in the atmosphere and thus act as prism after rainfall.

(iv) Water remains cool in a Earthenware pitcher. Due to evaporation as earthen pitchers have pores that allows evaporation.

(v) Milk is considered as an ideal food. It has all the minerals that one needs.

Q. 9. Which of the following statements are true or false. Only write “True” or “False” in the answer book. Do not reproduce the statement.
(i) Urea is a phosphate fertilizer. True
(ii) Cellulose is a natural polymer. True (Most abundant natural polymer)
(iii) Magnetite is the ore of copper. False (Iron)
(iv) Malaria is caused by drinking polluted water. False (Mosquito bite)
(v) The instrument used to measure velocity of wind is Barometer. False (Anemometer)
(vi) Our eye is very sensitive to blue light. False (green/red)
(vii) Sound can not travel through vacuum. True (Depends on compression and rarefaction)
(viii) Enzymes are biological catalyst. True
(ix) Leprosy is a disorder of Nervous System. False
(x) Mica is a non-conductor of electricity. True

Q.10 What are Endocrine glands? Name any four. From which part of the body are the followings secreted:

Pituitary Gland
Hypothalamus
Gonads
Thyroid
Adrenal Glands

(i) Insulin: Pancreas
(ii) Thyroxin: Thyroid
(iii) Adrenaline: Adrenal Medula
(iv) Oestrogen: Ovaries
(v) Testosterone: Testes
(vi) Cortisol: Adrenal Cortex

Q.14 Fill in the blanks with appropriate words:
(i) The purpose of computer is to Compute
(ii) polio is caused by Virus
(iii) The stalagmite is deposit of Calcium Carbonate
(iv) Bauxite is one of Aluminium Ores
(v) The chemical name of washing soda is Sodium Carbonate
(vi) The main constituent of Sui gas is Methane
(vii) Violet color has the shortest wave length.
(viii) Glass is a Super cooled liquid
(ix) Monomers of protein are Amino Acid
(x)Ascorbic acid is vitamin C
(xi)The solar system has 8 Planets
(xii) Aids is caused by HIV
(xiii) In a normal resting person the rate of heartbeat is 72
(xiv) The science which deals with heredity is known as Genetics
(xv) In Pakistan Copper mineral is found in Reqo Diq field
(xvi) The most abundant element in the earth crust is Silicon
(xvii) Barometer is an apparatus used for measuring the pressure of gases.
(xviii)The smallest branches of an artery lead into tiny blood vessels are called capillaries
(xix) The living part of a plant cell is composed of a nucleus and cytoplasm
(xx) The fastest revolving plant is mercury