Joint Examination Board
PABSON, Bhaktapur
Pre-send up Examination - 2066
Class: X F.M: 75
Subject: Science Time: 2.15 hrs. P.M: 30
Examinees are required to give their answers in their own words as far as possible. Priority will be given to creative answers in marking rather than the rot -learning.
Physics
Q.1. a. Write down the conclusion obtained from coin and feather experiment. The value of g is greater at the poles of the earth than that of the equator, why? A body weighs 84N on the earth's surface. What is the gravitational force on it due to the earth at a height of 4800km from the earth's surface? (Radius of the earth = 6400km) 1+1+2.5
b. What is energy crisis? Justify with two reasons that the hydroelectricity is the best alternative source of energy in the context of Nepal. 1+2
Q.2. a. State the Archimedes' principle. The dimension of a rectangular tank is 5m×5m×5m. If the tank is completely filled with water, find the liquid pressure at the base of the tank and on the surface of the tank. [density of water = 1000kg/m3, g = 10m/s2] 1+2.5
b. What is hydrometer? Study the figure and answer the following questions:
i. The object 'A' is floating in water, why? 1
ii. What happens when some amount of salt is added in it? 1
iii. If water level arose after immersing is 20cm3, what is the weight of floating object? (density of water = 1000kg/m3, g = 10m/s2)
Q.3. a. Define 1 calorie. What happens when given liquid (water) is cooled, why? Calculate the specific heat capacity of substance if it requires 25000J heat energy to raise the temperature of 20kg by 400C. 1+1+2
b. An object of 8cm height is placed at a distance of 20cm from a convex lens of focal length 40cm. Find the position and size of the image. A student sitting on the last bench can read his book but able to read the letters written on the white board by wearing spectacles only. What kind of defect does he have? Draw the diagram of such defect. 1+1+0.5+1.5
Q.4. a. Write the Fleming's right hand rule. Nichrome wire is used as heating element in heater, why? If 5A fuse is used in a line of 220V mains, how many 100 Watt bulbs can be safely lighted?
1.5+1+2
b. Write any one difference between electric motor and generator. Calculate the output voltage in a transformer if input voltage is 220V. The ratio of the number of turns is secondary to the primary coil is 0.30. 1+2
Chemistry
Q.5. a. What do you mean by lanthanides? Which one is reactive between 'F' and 'Cl'? Why? Change the given word equation into the balanced chemical equation. Write its type too. 1+0.5+1+0.5
i) Aluminium + Nitrogen Aluminium Nitride
b. Draw a well labeled diagram to show the laboratory preparation of ammonia gas. Write down the structural formula of Glycerol with one use. 2+1.5
Q.6. a. Which metal can be obtained from bauxite? Write the balanced chemical equation of chemical reaction between that metal and conc. Sulphuric acid. Why is HCl called acid? Write the name of neutral substance which is formed by reaction between HCl and NaOH. 0.5+2+1+0.5
b. Which glass will be formed if the mixture of silica and sodium carbonate is heated? Write its one special property and use. Environmentalists request to avoid the use of plastic, why? What effect on plants will be caused by the deficiency of phosphorus?
0.5+2+1+0.5
Biology
Q.7. a. Draw the figure of neurone and label its two parts. Write down the function of medulla oblongata. Virus is called an obligatory parasite, why? Name the virus that causes the mumps. 2+0.5+1+0.5
b. The wall of artery is thicker than that of veins, why? Write the function of platelets. Why is blood circulation important for our life? 1.5+1+1
Q.8. a. What is mitosis cell division? Name the type and stage of cell division given in the figure below. Mention any one feature of such type of cell division. Write one significance of such type of cell division. 1+1+1+1
b. How is secondary mycelium formed? Define pollination. Write the mode of reproduction in the following organisms. 1.5+1+1.5
i. Chlamydomonas
ii. Moss
iii. Bryophyllum
Q.9. a. What is mutation? Draw a chart to show both phenotype and genotype ratio of 1st generation of offspring obtained from pure white flowered pea plant (rr) and hybrid red flowered pea plant (Rr) according to Mendel's experiment. 1+2
b. What is food web? The rainfall with thunder in Chaitra-Baisakh is considered as good for farming in hilly region of Nepal, why? Give division or class of organism with following characteristics and other one character. 1+1.5+2×1
i) They have parallel venation in their leaves.
ii) They have mammary glands in the female.
Astronomy and Geology
Q.10. a.Write down the effects of the depletion of ozone layer. What is smog? How is mineral oil formed? 2+1+1.5
b.What is constellation? Why is blackhole invisible? Name the followings: 1+1+2
A This is an iceball that orbits the sun and looks like a broom when it approaches the sun.
B A small heavenly object vanishes before it reached the surface of the earth.
C The planet is red in colour.
D A small heavenly object which revolves round the sun mainly lie behind the orbits of Mars and Jupiter.
Best of Luck!
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