SEE 2081 Science Exam Solutions
View lumbini Province Science Question with Solution (Easy and detailed understandable solution.)
Section A: Multiple Choice Questions
Choose the best alternative to the following questions and write in the answer sheet.
(i) SVI
(ii) WAV
(iii) MOV
(iv) 3GP
Answer: WAV
(i) Adenine
(ii) Guanine
(iii) Cytosine
(iv) Thymine
Answer: Thymine
(i) respire through gills
(ii) Poikilothermic
(iii) Viviparous
(iv) have beak and feathers
Answer: have beak and feathers
(i) 65 N
(ii) 50 N
(iii) 35N
(iv) 15N
Answer: 35N
(i) 2.5 x 10^8 m/s
(ii) 1.24 x 10^8 m/s
(iii) 2.5 x 10^8 m/s
(iv) 3 x 10^8 m/s
Answer: 1.24 x 10^8 m/s
(i) 2 s
(ii) 4s
(iii) 10 s
(iv) 20 s
Answer: 4s
(i) Kerosene has higher temperature than water
(ii) Both of them have the same temperature
(iii) Kerosene has lower temperature than water
(iv) Heat does not affect temperature
Answer: Kerosene has higher temperature than water
(i) Magnetic effect
(ii) Effect of Electromagnetic induction
(iii) Mutual Induction effect
(iv) Motor effect
Answer: Motor effect
(i) Chalcopyrite (CuFeS2)
(ii) Argentite (Ag2S)
(iii) Hematite (Fe2O3)
(iv) Bauxite (Al2O3)
Answer: Chalcopyrite (CuFeS2)
Argument 1: insecticide not degrading quickly in the environment
Argument 2: Degrading gradually when it comes in contact with air and water
(i) Statement and argument 2 are correct but argument 1 is incorrect
(ii) Statement and argument 2 are incorrect but argument 1 is correct
(iii) Statement and both arguments are correct
(iv) Statement and both arguments are incorrect
Answer: Statement and both arguments are correct
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Section B: Very Short Answers
Write very short answers to the following questions.9×1=9
Answer:The fundamental units involved in force are kg, m, s⁻²
Answer: Both have a backbone (vertebrates).
Answer: Zebroid (or Zorse) is produced by the cross between zebra and horse
Answer: Any one suggestion to preserve to preserve endangered animals is:
Establish protected areas like national parks.
Answer:An instrument based on Pascal's law is Hydraulic press
Answer: It helps aquatic life survive in cold climates by keeping water liquid below ice.
Answer: 2Mg + O₂ → 2MgO
Answer: Roasting involves heating ore in the presence of oxygen, while calcination occurs in the absence or limited supply of oxygen.
Answer: Propan-2-ol
Section C: Short Answers
Write short answers to the following questions.14×2=28
Answer:
- Independent variable: The amount of stretch in the rubber band (controls the force applied).
- Dependent variable: The distance traveled by the piece of paper (depends on the stretch).
Answer:
i) Heart Structure: A rat has a four-chambered heart (two atria, two ventricles), while a snake has a three-chambered heart (two atria, one ventricle).
ii) Reproduction: Rats are viviparous (give birth to live young), while snakes are oviparous (lay eggs).
Answer:
i) Honey bees produce honey, a natural sweetener and medicinal substance.
ii) They pollinate flowers, aiding in plant reproduction and crop production.
Answer:
Offspring will be either pure tall (TT) or hybrid tall (Tt), all phenotypically tall.
Chart (Punnett Square):
| T | T | |
|---|---|---|
| T | TT | TT |
| t | Tt | Tt |
Answer:
Any two examples of non-granular leucocytes are:
i) Lymphocytes
ii) Monocytes
Answer:
i) Educate local communities about the identification and uses of medicinal plants.
ii) Promote sustainable harvesting practices to prevent depletion of plant resources.
Answer:
- Gravitational acceleration on Earth = 9.8 m/s², on Moon = 1/6 of Earth = 1.63 m/s².
- Weight on Earth = 100 kg × 9.8 m/s² = 980 N.
- Mass liftable on Moon = 980 N ÷ 1.63 m/s² ≈ 601.23 kg.
A person can lift approximately 601 kg on the Moon.
Answer:
i) It causes objects to fall toward the Earth’s surface.
ii) It keeps planets and moons in their orbits around the Sun or planets.
Answer:
- Formula: Q = m × c × ΔT
- m = 8 kg, c = 4200 J/kg°C, ΔT = 48°C - 30°C = 18°C
- Q = 8 × 4200 × 18 = 604,800 J
The heat required is 604,800 Joules.
Answer:
i) Light must travel from a denser medium to a rarer medium.
ii) The angle of incidence must be greater than the critical angle.
Answer:
i) A closed universe has density greater than the critical density and will eventually collapse, while an open universe has density less than the critical density and expands forever.
ii) A closed universe is finite and curved like a sphere, while an open universe is infinite and saddle-shaped.
Answer:
Unbalanced: NH₄Cl + Ca(OH)₂ → CaCl₂ + NH₃ + H₂O
Balanced: 2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2NH₃ + 2H₂O
Answer:
- Ethane: CH₃-CH₃
- Substituting two H atoms on each carbon with -OH: HO-CH₂-CH₂-OH
- IUPAC Name: Ethane-1,2-diol
- Structural Formula: HO-CH₂-CH₂-OH
Answer:
i) Wear protective gear like gloves and masks to avoid direct contact or inhalation.
ii) Apply pesticides during low-wind conditions to prevent drift to unintended areas.
Section D: Write long answers to the following questions:
Write long answers to the following questions.7×4=28
Answer:
Positive Impacts:
1. Improved Communication: Digital technology enables instant global communication through tools like email, video calls, and social media, connecting people across distances.
2. Access to Information: It provides vast resources via the internet, enhancing education and research opportunities for individuals worldwide.
Negative Impacts:
1. Health Issues: Excessive screen time can lead to eye strain, poor posture, and mental health problems like anxiety or addiction.
2. Privacy Concerns: Digital technology increases the risk of data breaches and loss of personal privacy due to widespread surveillance and hacking.
A = 1s², 2s² 2p⁶, 3s² 3p⁶, 4s¹
B = 1s², 2s² 2p⁶, 3s² 3p⁵
(i) Which one of the given elements is metal?
(ii) Write the period of element B on the basis of modern periodic table.
(iii) Write balanced chemical equation occurred when element A combines with element B.
Answer:
(i) Element Identification:
- A: 1s², 2s² 2p⁶, 3s² 3p⁶, 4s¹ → Atomic number = 19 (Potassium, K), a metal (alkali metal in Group 1).
- B: 1s², 2s² 2p⁶, 3s² 3p⁵ → Atomic number = 17 (Chlorine, Cl), a non-metal (halogen in Group 17).
Therefore, A (Potassium) is a metal.
(ii) Period of Element B:
- B has the configuration 1s², 2s² 2p⁶, 3s² 3p⁵.
- The highest principal quantum number (n) is 3, so B belongs to Period 3 in the modern periodic table.
(iii) Chemical Reaction:
- Potassium (K) reacts with Chlorine (Cl) to form Potassium Chloride (KCl).
- Unbalanced: K + Cl₂ → KCl
- Balanced: 2K + Cl₂ → 2KCl
(i) Write a balanced chemical equation of the reaction when the gas is passed into lime water.
(ii) Write an application of the gas in medical field.
(iii) Write the molecular formula of the compound formed when the gas is reacted with the gas having molecular mass 17 a.m.u.
(iv) How is the gas tested?
Answer:
- Egg shells are primarily CaCO₃, and the gas prepared is CO₂ (carbon dioxide) when reacted with an acid like HCl.
(i) Reaction with Lime Water:
- Lime water is Ca(OH)₂. When CO₂ is passed into it, it forms calcium carbonate (CaCO₃), turning the solution milky.
- Balanced equation: Ca(OH)₂ + CO₂ → CaCO₃ + H₂O
(ii) Medical Application:
- CO₂ is used in laparoscopic surgeries to inflate the abdominal cavity, providing space for surgeons to operate.
(iii) Reaction with Gas of 17 a.m.u.:
- Gas with molecular mass 17 a.m.u. is NH₃ (ammonia; N = 14, H₃ = 3).
- CO₂ + NH₃ → NH₂COONH₄ (ammonium carbamate, intermediate), but in presence of water, it forms ammonium carbonate.
- Molecular formula: (NH₄)₂CO₃ (ammonium carbonate).
(iv) Testing the Gas:
- Pass the gas through lime water (Ca(OH)₂ solution). If it turns milky due to the formation of CaCO₃, the gas is confirmed as CO₂.
Answer:
- No, there is no absence of the X chromosome in the semen. The couple having only sons is due to chance, as the father’s sperm carries both X and Y chromosomes, and only Y-carrying sperm fertilized the eggs.
Sex Determination in Humans:
- Humans have 46 chromosomes, including one pair of sex chromosomes (XX for female, XY for male).
- The mother always contributes an X chromosome (from XX).
- The father contributes either an X or Y chromosome (from XY), determining the child’s sex.
Chart (Punnett Square):
| Parent | Mother (X) | Mother (X) |
|---|---|---|
| Father (X) | XX (Female) | XX (Female) |
| Father (Y) | XY (Male) | XY (Male) |
- Probability: 50% chance of XX (female), 50% chance of XY (male).
- Role of Chromosomes: The Y chromosome carries the SRY gene, triggering male development. If the sperm carries Y, the offspring is male (XY); if X, the offspring is female (XX). Four sons indicate all fertilizations involved Y sperm, a statistical outcome, not an absence of X.
Answer:
Focal Length Calculation:
- Power (P) = -8 D
- Formula: P = 1/f (f in meters)
- -8 = 1/f
- f = 1/-8 = -0.125 m = -12.5 cm
-
Focal Length: -12.5 cm
Type of Lens:
- Negative power indicates a concave lens, used to correct nearsightedness (myopia).
Causes of This Defect (Myopia):
1. Elongated Eyeball: The eyeball is too long, causing light to focus in front of the retina.
2. Excessive Corneal Curvature: The cornea or lens is too curved, bending light too much and focusing it before the retina.
Answer:
Description of Diagram:
- The heart has four chambers: two atria (left and right) and two ventricles (left and right).
- Valves regulate blood flow between chambers and to arteries.
- (Since I can’t draw here, imagine a labeled heart diagram with:)
- Bicuspid Valve: Located between the left atrium and left ventricle (also called the mitral valve).
- Pulmonary Valve: Located between the right ventricle and pulmonary artery.
Labels:
- Bicuspid Valve: Prevents backflow from the left ventricle to the left atrium.
- Pulmonary Valve: Prevents backflow from the pulmonary artery to the right ventricle.
Answer:
Secondary Voltage Calculation:
- Given: Nₛ (secondary turns) = 10 × Nₚ (primary turns), Vₚ = 230 V
- Transformer formula: Vₛ / Vₚ = Nₛ / Nₚ
- Vₛ / 230 = 10 / 1
- Vₛ = 230 × 10 = 2300 V
- Secondary Voltage: 2300 V
Type of Transformer:
- Since Vₛ > Vₚ, it is a step-up transformer (increases voltage).
Use:
- Step-up transformers are used in power stations to increase voltage for efficient long-distance transmission over power lines, reducing energy loss.
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