SEE 2079 Lumbini Province — Science Past Paper

Full marks: 75 · Time: 2 hours 15 minutes · With step-by-step model answers in Nepali & English.

1. Q1.

   Group A - Write short answers to the following questions. (15 x 1 = 15)

   • (a) What is the value of acceleration due to gravity of the earth at the equator?
   • (b) Define upthrust.
   • (c) What is the specific heat capacity of water?
   • (d) What is the basis of Mendeleev's periodic law?
   • (e) Give an example of a displacement reaction.
   • (f) At which temperature does CO2 gas change into dry ice?
   • (g) What is called the chemical messenger in our body?
   • (h) What is the blood vessel called that carries blood from the heart to the lungs?
   • (i) Increment of which factor in the atmosphere causes acid rain?
   • (j) What is the ratio of dominant and recessive characters in the F2 generation of the pea plant in Mendel's experiment?
   • (k) Name the reaction that produces a large amount of energy in the sun.
   • (l) What does an inverter do?
   • (m) What is the plastic called that is affected by heat?
   • (n) Define chromosome.
   • (o) Who propounded the Nebular Hypothesis of the origin of the earth?
2. Q2.

   Under what conditions is the gravitational force equal to the universal gravitational constant?

3. Q3.

   All existing sources of energy are directly or indirectly obtained from the sun. Explain in two points.

4. Q4.

   A person wears glasses consisting of a lens of power +2D.

   • (a) What is the focal length of the lens?
   • (b) What is the defect of vision in the person?
5. Q5.

   Between a filament bulb and a CFL, which one helps to minimize load-shedding, and why?

6. Q6.

   A and B are two elements. A lies in the 1st group and 4th period of the periodic table, while B has atomic number 17.

   • (a) Write the electronic configuration of element A on the basis of sub-shells.
   • (b) Write the balanced chemical equation of the reaction between A and B. OR (for visually impaired only): What type of chemical reaction occurs between A and B?
7. Q7.

   Out of the metals Al, Cu, Fe and Ag, which one is used for the following purposes? Give reasons.

   • (a) When a heavy object is required.
   • (b) When a light and rust-free object is required.
8. Q8.

   A gas X is formed by the reaction of marble chips with an acid that gives hydrogen and chloride ions in water.

   • (a) Write the name and molecular formula of X.
   • (b) Write one chemical reaction to generate carbon from this gas. OR (for visually impaired only): What happens when the gas is passed into lime water?
9. Q9.

   Insecticides kill insects and help to increase crop yield, but environmentalists oppose the use of insecticides. Why? Give any two reasons.

10. Q10.

    The smallest unit of the nervous system is shown in the figure.

    • (a) Name part A.
    • (b) Write a function of part B. OR (for visually impaired only): Write any one function of each of the main two parts of the smallest unit of the nervous system.
11. Q11.

    A person has the following symptoms: a small round head, short body and a furrowed (protruding) tongue.

    • (a) What type of chromosome causes this?
    • (b) In a person of which sex does this disorder occur?
12. Q12.

    The result of cross-pollination between a round-seeded pea and a wrinkled-seeded pea is shown in the table:

    • (a) In which generation does this result appear?
    • (b) What is the difference between the pea plant having genes RR and the one having Rr?
13. Q13.

    Consider that your house is near a sugar factory. What suggestions would you give to reduce the pollution caused by the industry? Write any two points, mentioning the pollutants that cause different types of pollution.

14. Q14.

    When comets come closer to the sun, only then is the tail observed. Why? Write any two reasons.

15. Q15.

    Khaptad lies at a higher altitude than Dhangadhi from sea level. In which of these two places will an object weigh more? Give a reason and explain the relation.

16. Q16.

    For a convex lens, the magnification of the image is m < 1 for one position of the object and m > 1 for another position. Draw the suitable ray diagrams for these two conditions, along with one common characteristic. OR (for visually impaired only): On this basis, write the common nature of the image formed in the two conditions and one different nature also.

17. Q17.

    Three beakers A, B and C contain solutions of different compounds. The same indicator is added to all of them, and the solutions in A, B and C turn orange, yellow and red respectively.

    • (a) Write the name of the indicator used.
    • (b) Write the nature of the solution in beaker A.
    • (c) If the solution of beaker B is mixed with the solution of beaker C, write a chemical equation for the reaction involved. OR (for visually impaired only): What is the type of chemical reaction that occurs between the solutions of beaker B and beaker C?
18. Q18.

    An organic compound contains the elements C, H and O. It is also used in thermometers.

    • (a) Identify it and write its functional group.
    • (b) Write the IUPAC name of it.
    • (c) Write the name of the traditional method of preparing this compound.
19. Q19.

    Sketch a neat diagram of the stage of the silkworm that forms silk thread. Label the parts of this stage that help in breathing and that develop into legs in the adult stage. OR (for visually impaired only): Name the stage of the silkworm that forms silk thread. Also name the organ that helps in respiration and the organ that forms the legs in the adult stage. (Refer to the original diagram.)

20. Q20.

    Ramharidas has a problem of continuous bleeding from a simple injury. He went to a hospital to test his blood; the report is given in the table:

    • (a) Which blood cell is in a normal condition in his blood?
    • (b) Which disease may he be suffering from?
    • (c) Does the report show any other health problem? Write.
21. Q21.

    The temperature of 600 g of a certain metal is 100 °C. It is then placed in 300 g of water at 15 °C. If the final temperature of both becomes 20 °C, calculate the specific heat capacity of the metal. Also, how much heat must be supplied to raise the temperature of that metal by 20 °C?

22. Q22.

    A sodium hydroxide solution is reacted with hydrochloric acid, and then silver nitrate solution is added, giving a curdy white precipitate.

    • (a) The salt formed in the first step is invisible, but the white precipitate is visible in the second step. What is the reason for this?
    • (b) Write the balanced chemical equation for forming sodium nitrate from the salt prepared in the first step.
    • (c) What happens when sodium metal is used in place of sodium hydroxide in the first step?
23. Q23.

    A person wants to make a rose garden. Which technique is suitable to produce 20 rose plants in a short time from a single plant? Write the process of the technique. Why is this technique advantageous for agriculture, forestry and horticulture? Write any two other reasons.

24. Q24.

    A few years ago, people used refrigerators that produced a gas which destroys the earth's protective layer, so that more ultraviolet rays of the sun began to reach the earth's surface.

    • (a) Which gas produced from the refrigerator destroyed the protective layer of the earth? Write the name of that protective layer.
    • (b) How does the gas destroy the protective layer? Write its chemical equation. OR (for visually impaired only): Give one suggestion to control the destruction of the layer.
    • (c) Mention any one effect of this process on human health.
    • (d) Write any one negative impact on the Himalayan region.

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