SEE Science Solution 2074 Set: AC Course: New

By We-wec Yadav
  RE-111'AC'  

  Compulsory Science  

  SEE 2074 (2018)  

  Answer all the questions. 

(Group 'A')

15x1=15

  1. Write short answers of the following questions.

    1. Name two instruments that are based on the law of flotation.

      Instruments based on law of floatation are as follows :-

      1. Hydrometer like lactometer, alcoholometer, saccharometer, battery hydrometer, etc.
      2. Boats and ships.
      3. Flush tank of toilet.
      4. Automatic liquid volume indicator.


    2. Define nuclear reaction that takes place in the Sun.

      Nuclear reaction that takes place in the Sun is fusion reaction. Here 4 Hydrogen nuclii fuse together to form 1 Helium nucleus. The difference in mass between product and reactans is changed in from of heat and light.

      Or,

      In the Sun, light Hydrogen (1
      1       H      ) nuclii fuse together under extreme pressure and temperature to form heavy Helium(4
      2       He      ) nuclii and releasing energy in form of heat and light.



    3. Write the name of any two thermometric liquids.

      Mercury and Alcohol(Ethanol) are two thermometric liquids.



    4. Define power of lens.

      Power of a lens is defined as its ability to converge or diverge a parallel beam of ray falling on it.



    5. What is a step up transformer?

      A transformer which raises the voltage level of its input is called a step up transformer.



    6. Write the electronic configuration of potassium in terms of sub-shell.

      Electronic configuration of potassium(K) in terms of sub-shell1 :-
      s², 2s² 2p⁶, 3s² 3p⁶, 4s¹ .



    7. Write the relation between concentration of reactants and the rate of reaction.

      Rate of reaction increases with increase in concentration of reactants. This implies that, rate of reaction is directly proportional to the concentration of reactants.
      Mathematically,
      Rate of reaction ∝ concentration of reactants



    8. Define acid.

      An acid is a substance which is capable of giving a Hygrogen ion (H+) in aqueous solution.



    9. What are the atomic number and atomic weight of silver?

      The atomic number of silver is 47 and atomic weight of silver is 107.8682 a.m.u.



    10. In which stage of its life cycle does silkworm produce silk?

      Silkworm produces silk in Pupa phase



    11. What is cerebrospinal fluid?

      The fluid that flows in and around the hollow spaces of the brain and spinal cord, and between two of the meninges (the thin layers of tissue that cover and protect the brain and spinal cord) is called cerebrospinal fluid.



    12. Write any two examples of secondary air pollutants.

      Examples of secondary air pollutants are listed below :-
      1. Nitric acid
      2. Nitrogen dioxide (NO₂)
      3. Ozone (O₃)
      4. Particulate matter
      5. Peroxyacyl nitrates (PANs)
      6. Sulfuric acid


    13. What is external fertilization?

      External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body.



    14. Write second law of Mendel's related to heredity.

      Mendel's second law is also called "Law of segregation" or "Law of purity of gametes". This law states that two allels of a pair of gene seprate during the formation of gametes.



    15. What is galaxy?

      A galaxy is a huge collection of gas, dust, and billions of stars and their solar systems, all held together by gravity.




    (Group 'B')

    13x2=26


  2. In the given figure, weight of stone inside water is 9N and water displaced by stone is 2N then,

    1. What is the actual weight of stone?
    2. Which principle is this experiment based on?

    1. The actual weight of stone = weight of stone inside water + water displaced by stone = 9N + 2N = 11N
      The actual weight of stone is 11N.
    2. Above experiment is based on Archimedes' principle.



  3. In the present world, the uses of hydroelectricity is increasing. Write any two reasons.

    In the present world, the uses of hydroelectricity is increasing because of following reasons :-

    1. It is renewable source of energy.
    2. It is eco-friendly as it does not emit any harmful gases.
    3. Initially its capital investment seems too high but on long run its use also becomes economical.



  4. What are the main reasons of energy crisis? Write any two.

    The main reason of energy crisis are as folows:-
    1. Over population,
    2. Increasing demand,
    3. Industrialization,
    4. Urbanization,
    5. Limited uses renewable sources of energy,
    6. Limited stock of non-renewable sources of energy,
    7. Misuse of energy and
    8. Lack of technology to build machine with efficiency around 100%.


  5. In winter morning as soon as we wake up, the air inside the room is cold but if we go out and return to the same room, we feel warm, why?

    Temperature inside blanket is higher than indoor ambient temperature so when we wake up and came out of blanket then our body came in contact with lower temperature and we feel cold.
    But outdoor ambient temperature is lower than indoor temperature, so when we went out and returned back to the same room we actually moved to higher temperature zone. That is why we feel warm.


  6. Study the electronic configuration given below and answer the following:-
    A - 1s2, 2s2 2p6, 3s2
    B - 1s2, 2s2 2p6, 3s2 3p5

    1. Write the name of elements A and B.
    2. Write the balanced chemical equation of chemical reaction occurs between these two elements.

    1. Element A is Magnesium(Mg) and element B is Chlorine(Cl).
    2. Mg + 2Cl → MgCl₂


  7. Write the example of each catalyst that accelerates and decelerates the rate of chemical reaction along with the balanced chemical reaction.

    Manganese dioxide(MnO₂) accelerates the decomposition of Hydrogen Peroxide(H₂O₂) into water(H₂O) and Oxygen(O₂).
    2H₂O₂MnO₂
                ➤     2H₂O + O₂↑

    Glycerine(C₃H₅(OH)₃) decelerates the decomposition of Hydrogen Peroxide(H₂O₂) into water(H₂O) and Oxygen(O₂).
    2H₂O₂Glycerine
                ➤     2H₂O + O₂↑


  8. Write any two properties of acid.

    Properties of acid are:-
    1. Acid turns blue litmus paper into red.
    2. It tastes sour.
    3. Produces salt and water when reacted with base.


  9. Write two properties of aluminium that make it suitable for building body parts of the aeroplane.

    Following are the properties of aluminium that make it suitable for building body parts of the aeroplane :-
    1. Specific gravity:-
      It's density is 2.7 g.cm⁻³ at 20 °C. This lower density makes Aluminium a best construction material for aircrafts among various corrosive resistant metal.
    2. Corrosion resistant:-
      Aluminium is chemically more resistant to moisture than various metals. There are various lighter metals than Aluminium but their highly reactive nature make them unsuitable.
    3. Abundance:-
      It is the third most abundant element and the most abundant metal in the Earth's crust.


  10. Which stage in the life cycle of silkworm will be affected immediately if the mulberry bush dies suddenly? Clarify with reason.

    Larva stage will be affected immediately if the mulberry bush dies suddenly.
    A silkworm only eats in this stage and eats voraciously for almost 1 month. It gets all the energy required for growth, metamorphosis and survival in larva stage. So if the mulberry bush dies suddenly larva can't survive further.


  11. Identify the blood vessel given and label the parts A, B and D.

    The blood vessele given here is  "vein" .

    Label Parts
    A Endothelium
    B Connective tissue
    C Smooth muscle
    D Valve


  12. Write any two differences between male and female gamete in two points.

    Differences between male gamete and female gamete are given below:-
    Male gamete Female gamete
    It is also called a sperm. It is also called an egg.
    Male gamete is heterogametic.
    It has both X chromosome and Y chromosome.    		 Female gamete is homogametic.
    It has only X chromosome.
    Sex chromosome type of male gamete determines sex of the the child. Female gamete is not reponsible for formation of zygote but it does not determine sex of the child.
    [Main Page] Differences between male gamete and female gamete


  13. Write two probable causes that Mendel did not do his experiment in frog instead of pea.

    Mendel did not do his experiment in frog instead of pea probably because of following reasons :-
    1. Time consuming :- A female frog takes 4 years to lay eggs. So,it may take a decade just to observe two generations.
    2. Expensive :- Monitoring frogs activities in a controlled environment is a challenging an expensive task in itself. It requires a lot of resources.
    3. Finding mating partner with same characteristics is rare.


  14. State two differences between meteors and meteorites.

    Differences between meteors and meteorites are given below:-
    Meteors Meteorites
    When meteoroids enter Earth’s atmosphere (or that of another planet, like Mars) at high speed and burn up, the fireballs or “shooting stars” are called meteors. When a meteoroid survives a trip through the atmosphere and hits the ground, it’s called a meteorite.
    Meteors are not considered as dangerous as they not reache the Earth's surface. Meteorites are considered dangerous as they reache the Earth's surface.
    It looks like shower of light. its appearance is like stone and pebbles of the Earth.
    [Click to see main Page] Differences between meteors vs meteorites



    15. (Group 'C')

    6x3=18


  15. The different weights of a piece of stone on weighing in three different media - air, fresh water and salt solution are given in the table. Answer the following questions by observing given table.

     Medium  Weight 
    X12 N
    Y18 N
    Z14 N

    1. Identify water, air and salt solution among X, Y and Z
    2. If the weight of 1kg mass in air is 10N, what will be the mass of the given stone?
    3. Find the upthrust experienced by the stone?

    1. Medium X is "salt solution", medium Y is "air" and medium Z is "water".

    2. Solution
      Given
      Weight of the stone in air = 18N
      1 kg mass in air = 10N.
      1N = 1 ÷ 10 kg = 0.1kg
      So, 18N = 18 × 0.1 kg = 1.8 kg
      ∴ Weight of the stone = 1.8 kg.

    3. Upthrust experienced by the stone in water = 18N - 14N = 4N
      Upthrust experienced by the stone in salt solution = 18N - 12N = 6N


  16. In the given diagram C2 has 1/5 coil of C1. If the input voltage is 1200V, what will be the output voltage? What is the reason behind laminating the core of this device?

    Solution

Input voltage, V₁ = 1200v.

Let

Number of turns in secondary coil C2 = N₂ 

Number of turns in secondary coil C1 = N₁

Output voltage = V₂.

From question,

      1
N₂ =     N₁
      5

  N₂       1
      =      
  N₁       5

 From the transformer ratio, we have

  N₂       V₂
      =      
  N₁       V₁

       V₂       1
Or,        =      
       V₁       5

         V₂         1
Or,            =      
       1200 V       5

            1      240 V
Or, V₂ =       1200 V
            5 

∴ V₂ = 240 V.
     Hence the output voltage will be 240 V. 
    Laminated core dissipates less amount of heat than a single block of iron core would. Hence laminated core reduces core loss in transformer and increases transformer efficiency. That is why, core of transformer is laminated.


  17. Draw a diagram of laboratory preparation of carbondioxide gas. Name two chemicals used for this process.


    The two chemicals used for this process are Hydrochloric acid(HCl) and Calcium Carbonate(CaCO₃)

  18. Write any two applications of thermosetting and thermoplastics. Mention any two characteristics of plastics.

    Two applications of thermosetting plastics are as follows:-
    1. It is used for making plugs, switches and board.

    2. It is used for making hadles of kitchenware like cooker, pan, kettle, etc.

    3. Teflon is used for making coating of non-sticky cookwares.

    [Click to see main Page] applications of thermosetting plastics

    Two applications of thermoplastics are as follows:-
    1. It is used for making PPE(Personal protection equipment).

    2. It is used for making bags to wrap, pack or carry goods.

    3. It is also used as container for various item like medicine, cream, grocessary items etc

    4. It is used for making drinking bottles.

    5. It is used for making water poly tanks.

    [Click to see main Page] applications of thermoplastics

    Two characteristics of plastics are as follows:-
    1. Light :-It is light in weight.

    2. Chemicaly inactive :-Water, moisture and air can't corrode plastics. Even it is not affected by various acids and other chemicals.

    3. Transparency :-A plastics comes transparecy rangees from a transparent object to an opaque object.

    [Click to see main Page] Characteristics of plastics


  19. Draw diagrams for each Metacentric, Sub-metacentric and Telocentric chromosomes.



    Metacentric Chromosome

    Sub-metacentric Chromosome

    Telocentric Chromosome




  20. How does artificial reproduction help in the excess production of fruits?

    From artificial reproduction cloned disease resistant and vibrant plant can be chosen for reproduction. Such plants would bear good quality fruits on it. Reproduction cycle of fruits can be shortened. Not only reproduction cycle even a new plant able to bear fruits can be grown in short that that would be required naturally. All these outcomes are possible from artificial reproduction. This is how, artificial reproduction help in the excess production of fruits.



    21. (Group 'D')

    4x4=16


  21. In the figure below, two identical metal balls A and B having equal masses are being dropped towards the surface of moon and earth. Analyse the given data and answer the following questions:

    1. If both the metal balls are released simultaneously, which one does strike the ground faster? Show with calculation.
    2. A person lifts 30kg on the surface of the earth. How much mass can he lift on the surface of the moon if he applies same magnitude of force?

    1. In case of the moon :-

      Given

      Distance, s = 10 m

      Acceleration, a = 1.62 m/s²

      Initial velocity, u = 0

      Time, t = ?

      S = u t + ½ a t²

      10 m = 0 × t + ½ × 1.62 m/s² × t²

      10 m = 0.81 m/s² × t²

      t² = 10 / 0.81 s² = 12.346 s²

      ∴ t =3.514 s


      In case of the Earth :-

      Given

      Distance, s = 10 m

      Acceleration, a = 9.8 m/s²

      Initial velocity, u = 0

      Time, t = ?

      S = u t + ½ a t²

      10 m = 0 × t + ½ × 9.8 m/s² × t²

      10 m = 4.9 m/s² × t²

      t² = 10 / 4.9 s² = 2.041 s²

      ∴ t =1.429 s

      Here from the above calculations it is seen that time in case of the Earth is smaller than in case of the moon. So, the ball falling on the Earth will strike the ground faster.


    2. Given

      Mass of the ball, m = 30 Kg

      Acceleration due to gravity at the earth surface, g = 9.8 m/s²

      Force applied, F = m.g = 30 kg × 9.8 m/s² = 294 N.

      On the moon :-

      Acceleration due to gravity at the earth surface, g = 1.62 m/s²

      Force applied, F = 294 N

      Mass that can be lifted on the surface of the moon = 294/1.62 Kg = 181.481 Kg

      181.481 Kg mass can he lift on the surface of the moon if he applies same magnitude of force as on the Earth's surface.


  22. Study the structural formula given below and answer the following questions:

    1. Write the IUPAC name of it.
    2. In which group of organic compound is it kept?
    3. Which type of hydrocarbon is formed if three 'OH' are replaced by three 'H' atom?
    4. Give two reasons to use this compound in fruits and food materials.

    1. Its IUPAC name is 1,2,3-Propanetriol .

    2. It is kept in trihydric alcohol group.

    3. Propane (C₃H₈) is formed if three 'OH'of glycerol are replaced by three 'H' atoms.

    4. Reasons for which glycerol is used in fruits and food materials are as follows :-
      1. Moisturizing agent :- Its moisturizing property prevents fruits and food materials from drying.

      2. Sweetening agent (sugar alcohol) :- It is used to add sweet taste to food materials instead of sucrose (Table sugar C₁₂H₂₂O₁₁).



  23. Draw the diagram of neuron and label dendrite and axon. Clarify the role of neuron when one suddenly touch the hot body.


    Neuron is drawn below:-
    Neuron.


    When we touch a hot body, we immediately move apart from that hot body. This action is instantaneous and automatic. Such action lies in reflex action category. here neuron plays an important role. Neuron's role here can be described in three terms. These terms are as follows :-

    1. Afferent nerve :- Neurons takes the sensory impulse from the receptor organ to the spinal cord.

    2. Relay neuron :- Neuron in spinal cord which changes the sensory impulse into motor impulse.

    3. Motor or Efferent Nerve :- Carries the motor impulse from the spinal cord to the effector organ so that receptor organ can be moved apart from the hot body.


  24. Explain the process of formation of mineral oil with diagram. Give a reason to minimize consumption of mineral oil in the country like Nepal.

    Minerals oils are formed in nature and it takes millions of years long process. They are formed from dead body of microorganism deposited and piled-up at a place inside seas and oceans. Formation of mineral oil can be summed up in following points:-
    1. Microorganism living millions of years ago died.

    2. Bacteria decayed those dead bodies.

    3. These decayed bodies get covered by various layers of sand and soil.

    4. Due to exposure to pressure and temperature over long period sand and soil piled up form an impervious layer of sedimentary rock.

    5. This temperature and pressure is also responsible for conversion of dead remnant of microorganism into mineral oil inside impervious layer of sedimentary rocks.

    Formation of mineral oils.


    Country like Nepal should minimize the consumption of mineral oil because they have huge hydropower potential.

Or,

Following are the reasons that shows why country like Nepal should minimize consumption of mineral oil :-
  1. Nepal has hydropower potentiality of 83,000 MW.

  2. Nepal does not have any mineral oil source of its own. So it has to spen a lot of money to import mineral oils from abroad.

  3. To reduce net carbon emission by Nepal.

Location: Kathmandu 44600, Nepal

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