PABSON SEE PRE BOARD EXAMINATION-2082 Science Solution | Set 1041 ‘B’

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PABSON SEE PRE BOARD EXAMINATION-2082

Compulsory Science & Technology Solution

Set: 1041 ‘B’ | Full Marks: 75 | Time: 3 Hours | Date: 2082-10-26

Welcome to the complete solution for the

PABSON SEE PRE BOARD Exam 2082 Science Paper

. Below you will find detailed answers for all sections (A, B, C, and D) in both Nepali and English mediums.

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Section A: Multiple Choice Questions (MCQs)
Section B: Very Short Answer Questions
Section C: Short Answer Questions
Section D: Long Answer Questions
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Section ‘A’: Multiple Choice Questions (10 × 1 = 10)

1(a) Which of the following is the derived unit represented by the group $kgm^{2}s^{-3}$?
(तल दिइएका मध्ये कुन तत्जन्य एकाई आधारभूत एकाइहरू $kgm^{2}s^{-3}$ द्वारा प्रतिनिधित्व गरिने एकाइ हो ?)

(i) Pascal (पास्कल)
✓ (ii) Watt (वाट)
(iii) Joule (जुल)
(iv) Newton (न्यूटन)

Reason: $Power = \frac{Work}{Time} = \frac{Force \times Distance}{Time} = \frac{(kg \cdot m/s^2) \times m}{s} = kg \cdot m^2 \cdot s^{-3}$.
Marks: 1

1(b) Raunak observed two organisms A and B in the laboratory. Organism A was bilaterally symmetrical and dorsoventrally flattened like a leaf, and organism B was bilaterally symmetrical, cylindrical, and tapering at both ends. Under which phylum should A and B be placed?
(रौनकले प्रयोगशालामा दुई जीव A र B अध्ययन गरे । जीव A पात जस्तो चेप्टिएको र बाइलेटेरल्ली सिमेट्रिकल थियो भने जीव B बेलनाकार, बाइलेटेरल्ली सिमेट्रिकल र दुबै छेउमा सानो हुँदै गएको थियो । A र B लाई कुन फाइलम अन्तर्गत राख्न सकिन्छ ?)

(i) A → Nemathelminthes, B → Annelida
(ii) A → Annelida, B → Platyhelminthes
✓ (iii) A → Platyhelminthes, B → Nemathelminthes
(iv) A → Platyhelminthes, B → Annelida

Reason: Organism A (flattened) is a Flatworm (Platyhelminthes). Organism B (cylindrical/tapering) is a Roundworm (Nemathelminthes).
Marks: 1

1(c) Which of the following correctly describes the structural nature of RNA?
(तल दिइएका मध्ये कुन विकल्पले आरएनएको संरचनात्मक विशेषता वर्णन गर्छ ?)

(i) Double-stranded structure containing uracil (दुई स्ट्रान्ड भएको संरचना जसमा युरासिल हुन्छ ।)
(ii) Single-stranded structure containing thymine (एकल स्ट्रान्ड भएको संरचना जसमा थाइमिन हुन्छ ।)
✓ (iii) Single-stranded structure containing uracil (एकल स्ट्रान्ड भएको संरचना जसमा युरासिल हुन्छ ।)
(iv) Double-stranded structure containing thymine (दुई स्ट्रान्ड भएको संरचना जसमा थाइमिन हुन्छ ।)

Marks: 1

1(d) Which part of the given plant is used as medicine?
(दिइएको विरुवाको कुन भाग औषधिको रूपमा प्रयोग हुन्छ ?)

(i) Fibrous root, because it stores curcumin and aromatic oils. (रेशेदार जरा, किनभने यसले कर्क्युमिन र सुगन्धित तेलहरू रहेको हुन्छ ।)
✓ (ii) Rhizome, because it contains the highest concentration of curcumin. (राइजोम, किनभने यसमा कर्फ्यूमिनको मात्रा सबैभन्दा बढी हुन्छ ।)
(iii) Stem, because it turns into the powdered form after drying. (काण्ड, किनभने सुकाएपछि यसलाई पाउडरको रूपमा तयार गर्न सकिन्छ ।)
(iv) Tuber, because it develops the yellow pigment in underground parts. (ट्युबर, किनभने भूमिगत भागमा पहेंलो रंग उत्पन्न हुन्छ ।)

Marks: 1

1(e) A meteoroid is falling at a distance of 12800 km from the centre of the Earth. The mass of Earth is $6 \times 10^{24} kg$. What is the acceleration due to gravity at that point?
(एक उल्कापिण्ड पृथ्वीको केन्द्रबाट 12800 कि.मि. दुरी टाढाबाट खस्दैछ । यदि पृथ्वीको पिण्ड $6 \times 10^{24} kg$ रहेछ भने सो स्थानमा गुरुत्व प्रवेग कति हुन्छ ?)

(i) $1.6 \ m/s^{2}$
(ii) $9.8 \ m/s^{2}$
✓ (iii) $2.45 \ m/s^{2}$
(iv) $25.6 \ m/s^{2}$

Calculation: $g = \frac{GM}{R^2}$. Here $R = 2 \times Radius \ of \ Earth$ approx. Since $g \propto 1/R^2$, if distance doubles, $g$ becomes $1/4$th of $9.8$, which is approx $2.45$.
Marks: 1

1(f) Study the following statements related to heat. Which of them is correct?
(तापसँग सम्बन्धित तलका कथनहरू अध्ययन गर्नुहोस् । तीमध्ये कुन कथन सही छ ?)

(i) Amount of heat is inversely proportional to the kinetic energy of the molecules. (तापको मात्रा अणुहरूको गतिशक्तिसँग प्रत्यक्ष व्युतक्रमानुपाती हुन्छ ।)
✓ (ii) Specific heat capacity is inversely proportional to change in temperature. (विशिष्ट ताप धारण क्षमता तापक्रमको परिवर्तनसँग व्युतक्रमानुपाती हुन्छ ।)
(iii) The amount of heat lost is inversely proportional to the mass of the body. (वस्तुले गुमाइएको तापको मात्रा वस्तुको पिण्डसँग व्युतक्रमानुपाती हुन्छ ।)
(iv) The amount of heat is inversely proportional to specific heat capacity. (तापको मात्रा विशिष्ट ताप क्षमतासँग व्युतक्रमानुपाती हुन्छ ।)

Context: For the same amount of heat supplied to the same mass, a substance with higher specific heat capacity shows a smaller change in temperature ($s \propto 1/dt$).
Marks: 1

1(g) Study the following statement and the arguments:
(तल दिइएको कथन र तर्कहरू अध्ययन गर्नुहोस्ः)
Statement: Electricity can be generated due to the relative motion of the conductor coil and magnetic flux.
Argument 1: The induced emf is directly proportional to the rate of change of magnetic flux.
Argument 2: The emf continues to induce even when the magnetic flux stops changing.

(i) Statement and argument 2 are correct but argument 1 is incorrect (कथन र तर्क २ सही छन् तर तर्क १ गलत ।)
(ii) Statement and argument 1 are incorrect but argument 2 is correct (कथन र तर्क १ गलत छन् तर तर्क २ सही छ ।)
✓ (iii) Statement and Argument 1 is correct, but argument 2 is incorrect (कथन र तर्क १ सही छन् तर तर्क २ गलत छ ।)
(iv) The statement is correct but both arguments are incorrect (कथन सही छ तर दुवै तर्कहरू गलत छन् ।)

Marks: 1

1(h) What will be the future of the universe if the average density of the universe is more than the critical density?
(यदि ब्रह्माण्डको औसत घनत्व चरम घनत्वभन्दा बढी भएमा, ब्रह्माण्डको भविष्य के हुन्छ ?)

(i) Open universe (खुला ब्रह्माण्ड)
✓ (ii) Closed universe (बन्द ब्रह्माण्ड)
(iii) Flat universe (समतल ब्रह्माण्ड)
(iv) Paper like universe (कागजजस्तै ब्रह्माण्ड)

Marks: 1

1(i) Why do electrons enter the 4s orbital before the 3d orbital?
(इलेक्ट्रोनहरू 3d कक्षभन्दा पहिले 4s कक्षमा किन प्रवेश गर्छन् ?)

(i) The 4s orbital holds fewer electrons than the 3d orbital. (4s कक्षले 3d कक्षभन्दा कम इलेक्ट्रोन राख्छ ।)
(ii) The 4s orbital is easier to occupy because of its larger size. (4s कक्ष ठूलो भएकाले यसमा इलेक्ट्रोन सजिलै प्रवेश गर्छ ।)
(iii) The 4s orbital lies closer to the nucleus than the 3d orbital. (4s कक्ष 3d कक्षभन्दा न्यक्लियसको नजिक हुन्छ ।)
✓ (iv) Orbitals with lower energy are filled first. (कम ऊर्जायुक्त कक्षहरू पहिले भरिन्छन् ।)

Marks: 1

1(j) Identify the correct statement regarding food preservatives and ripening agents:
(तलका कुन कथन खाद्य परिरक्षी र फल पकाउने पदार्थबारे सही हो ?)

✓ (i) Primary preservatives are naturally derived and can be added to food in necessary quantities. (प्राथमिक खाद्य परिरक्षीहरू प्राकृतिक रूपमा प्राप्त हुन्छन् र आवश्यक मात्रामा खाद्य पदार्थमा थप्न सकिन्छ ।)
(ii) Secondary preservatives are natural and permitted only in restricted amounts in food. (द्वितीय श्रेणीका खाद्य परिरक्षी प्राकृतिक हुन्छन् र सीमित मात्रामा मात्र खाद्य पदार्थमा प्रयोग गर्न सकिन्छ ।)
(iii) Calcium Carbide is a conventional fruit-ripening substance. (क्याल्सियम कार्बाइड परम्परागत फल पकाउने पदार्थ हो ।)
(iv) High consumption of fruit ripening agents helps to maintain good health. (फलफूल पकाउने पदार्थको अत्यधिक सेवनले राम्रो स्वास्थ्य राख्न मदत गर्छ ।)

Marks: 1

Section ‘B’: Very Short Answer Questions (9 × 1 = 9)

2(a) Why is digital well-being important?
(डिजिटल आरोग्यता किन आवश्यक पर्दछ ?)

English: Digital well-being is important to maintain a balance between technology use and physical/mental health, reduce stress and eye strain, and improve focus and relationships.

Nepali: प्रविधिको प्रयोग र शारीरिक/मानसिक स्वास्थ्य बीच सन्तुलन कायम राख्न, तनाव र आँखाको थकान कम गर्न, तथा एकाग्रता र सम्बन्ध सुधार गर्न डिजिटल आरोग्यता आवश्यक पर्दछ ।

Marks: 1

2(b) Why is a whale called a mammal?
(वेललाई किन स्तनधारी जनावर भनिन्छ ?)

English: A whale is called a mammal because it gives birth to young ones directly, breastfeeds them, possesses lungs for breathing, and is warm-blooded.

Nepali: वेलले सिधै बच्चा जन्माउने, बच्चालाई दूध चुसाउने, सास फेर्न फोक्सो हुने र यो समतापी (warm-blooded) हुने भएकोले यसलाई स्तनधारी जनावर भनिन्छ ।

Marks: 1

2(c) Why is meiosis called reductional cell division?
(मियोसिस कोष विभाजनलाई किन रिडक्सनल कोष विभाजन भनिन्छ ?)

English: Meiosis is called reductional cell division because the number of chromosomes in the daughter cells is reduced to half of that in the parent cell.

Nepali: मियोसिस कोष विभाजनमा बन्ने नयाँ कोषहरूमा क्रोमोजोमको संख्या माउ कोषको भन्दा आधा हुने भएकोले यसलाई रिडक्सनल (न्यूनिकरण) कोष विभाजन भनिन्छ ।

Marks: 1

2(d) Water pipe in Ramesh’s house burst during the winter season. He noticed that the temperature had dropped below $0^\circ C$ for several days. Identify the cause.
(रमेशको घरमा पानीको पाइप जाडो मौसममा फुट्यो । उनले केही दिनसम्म तापक्रम $0^\circ C$ भन्दा तल झरेको थाहा पाए । यसको कारण पहिचान गर्नुहोस् ।)

English: The cause is the anomalous expansion of water. Water expands when it freezes into ice below $4^\circ C$, exerting pressure on the pipe walls causing them to burst.

Nepali: यसको मुख्य कारण पानीको असाधारण प्रसार (Anomalous expansion) हो । $०^\circ C$ मा पानी जमेर बरफ बन्दा यसको आयतन बढ्छ, जसले पाइपमा अत्यधिक चाप सिर्जना गरी पाइप फुटाउँछ ।

Marks: 1

2(e) Where must an object be placed in front of a convex lens so that the image formed is upright and magnified?
(कन्भेक्स लेन्सबाट बनेको प्रतिबिम्व वस्तुभन्दा ठूलो र सुल्टो हुनका लागि वस्तुलाई कहाँ राख्नुपर्छ ?)

English: The object must be placed between the Focus (F) and the Optical Centre (O).

Nepali: वस्तुलाई लेन्सको फोकस (F) र अप्टिकल सेन्टर (O) को बिचमा राख्नुपर्छ ।

Marks: 1

2(f) Which force is responsible for holding the universe firmly?
(कुन बलले गर्दा ब्रह्माण्डमा रहेका पिण्डहरुलाई बाँधेर राखेको छ ?)

English: Gravitational force.

Nepali: गुरुत्वाकर्षण बल ।

Marks: 1

2(g) How many periods and groups are there in the modern periodic table?
(आधुनिक पेरियोडिक तालिकामा कति पिरियड र कति ग्रुप छन् ?)

English: There are 7 periods and 18 groups.

Nepali: यसमा ७ पिरियड र १८ ग्रुपहरू हुन्छन् ।

Marks: 1

2(h) Metal ‘A’ is in Group 2 (IIA), Period 4, and non-metal ‘B’ is in Group 16 (VIA), Period 2 of the modern periodic table. Write the chemical formula of the compound formed when A reacts with B.
(धातु ‘A’ आधुनिक पेरियोडिक तालिकाको ग्रुप 2 (IIA), पिरियड ४ मा पर्छ र अधातु ‘B’ ग्रुप 16 (VIA), पिरियड 2 मा पर्छ । A र B प्रतिक्रिया गर्दा बन्ने यौगिकको रासायनिक सूत्र लेख्नुहोस् ।)

English: Metal A is Calcium (Ca, Valency 2) and Non-metal B is Oxygen (O, Valency 2). The formula is CaO (Calcium Oxide).

Nepali: धातु A क्याल्सियम (Ca) हो र अधातु B अक्सिजन (O) हो । बन्ने यौगिकको सूत्र CaO हो ।

Marks: 1

2(i) Write the structural formula of monohydric alcohol used as an alcoholic beverage.
(मादक पेय पदार्थका रूपमा प्रयोग हुने मोनोहाइड्रिक अल्कोहलको संरचनात्मक सूत्र लेख्नुहोस् ।)

English: The alcohol is Ethanol ($C_2H_5OH$). Structural Formula: $$H \quad H$$ $$| \quad |$$ $$H – C – C – O – H$$ $$| \quad |$$ $$H \quad H$$

Nepali: यो इथेनल ($C_2H_5OH$) हो । संरचनात्मक सूत्र माथि देखाइएको छ ।

Marks: 1

Section ‘C’: Short Answer Questions (14 × 2 = 28)

3. Why can’t we use the formula $s = \frac{v}{t}$ to calculate the distance travelled by a moving body? Justify your answer by checking the units.
(चालमा रहेको वस्तुले तय गरेको दूरी गणना गर्न सूत्र $s = \frac{v}{t}$ किन प्रयोग गर्न सकिदैन ? एकाइ जाँच गरी आफ्नो उत्तर पुष्टि गर्नुहोस् ।)

उत्तर (Answer):

English: The formula $s = v/t$ is incorrect because distance is the product of velocity and time ($s = v \times t$), not division. Unit Check: LHS Unit (Distance) = meter ($m$) RHS Unit ($v/t$) = $(m/s) / s = m/s^2$ (which is acceleration). Since $m \neq m/s^2$, the formula is dimensionally incorrect.

Nepali: सूत्र $s = v/t$ गलत छ किनभने दुरी भनेको गति र समयको गुणनफल हो ($s = v \times t$), भागफल होइन । एकाइ जाँच गर्दा: बायाँ तर्फ दुरीको एकाइ मिटर ($m$) हुन्छ तर दायाँ तर्फ ($v/t$) को एकाइ $m/s^2$ हुन्छ । तसर्थ यो सूत्र गलत छ ।

Marks: 2

4. List out any two characteristics of class Gymnosperm.
(जिम्नोस्पर्म वर्गका कुनै दुई विशेषताहरू लेख्नुहोस् ।)

उत्तर (Answer):

English:

They bear naked seeds (seeds are not enclosed inside the fruit).
They produce male and female cones separately (usually unisexual).

Nepali:

यिनीहरूमा नाङ्गो बीउ हुन्छ (बीउ फलभित्र छोपिएको हुँदैन) ।
यिनीहरूले भाले र पोथी कोनहरू छुट्टाछुट्टै उत्पादन गर्छन् ।

Marks: 2

5. Observe the three different types of honey bees in a hive. Justify that the reproduction of the ‘C’ type honey bee is unique in sexual reproduction but not of the ‘A’ type and ‘B’ type.
(मौरीको घारमा पाइने तीन किसिमका मौरीहरू अध्ययन गर्नुहोस् । ‘C’ किसिमको मौरीमा हुने प्रजनन ‘A’ र ‘B’ किसिमको मौरीको तुलनामा विशेष प्रकारको हुन्छ भन्ने कुरा पुष्टि गर्नुहोस् ।)

उत्तर (Answer):

English:

A & B (Queen/Worker) reproduce sexually from fertilized eggs.
C (Drone) reproduces from an unfertilized egg through a process called Parthenogenesis, which is unique.

Nepali:

A र B (रानी र कर्मी) निषेचित फुलबाट (sexual reproduction) बन्छन् ।
C (भाले/ड्रोन) अनिषेचित फुलबाट पार्थेनोजेनेसिस (Parthenogenesis) प्रक्रियाद्वारा बन्छन्, जुन विशेष प्रकारको हो ।

Marks: 2

6. Illustrate the $F_1$ generation obtained by crossing a pure tall pea plant with a pure dwarf pea plant. Also, state which of Mendel’s laws is demonstrated by this result.
(शुद्ध अग्लो केराऊको बोट र शुद्ध होचो केराऊको बोटवीच पर-परागसेचन गर्दा प्राप्त हुने $F_1$ पुस्तालाई चित्रसहित देखाउनुहोस् । साथै, यस नतिजाले मेन्डेलको कुन नियमलाई प्रमाणित गर्छ, उल्लेख गर्नुहोस् ।)

उत्तर (Answer):

English:

Parent: TT (Tall) × tt (Dwarf)
F₁ Genotype: Tt (Hybrid Tall)
Phenotype: All Tall
This demonstrates Mendel’s Law of Dominance.

Nepali:

माउ बोट: TT (अग्लो) × tt (होचो)
F₁ जेनोटाइप: Tt (वर्णशंकर अग्लो)
फेनोटाइप: सबै अग्ला
यसले मेन्डेलको प्रबलताको नियम (Law of Dominance) देखाउँछ ।

Marks: 2

7. What happens when the number of platelets is abruptly increased or decreased in our blood?
(हाम्रो रगतमा प्लेटलेट्सको संख्या अत्याधक मात्रामा बढे वा घटेमा के हुन्छ ?)

उत्तर (Answer):

English:

High count of platelets leads to Thrombocytosis (risk of blood clotting inside vessels).
Low count leads to Haemophilia or delayed clotting (excessive bleeding).

Nepali:

उच्च संख्या: थ्रोम्बोसाइटोसिस (रगत नसाभित्रै जम्ने जोखिम) ।
न्यून संख्या: हेमोफिलिया (रगत नजम्ने वा धेरै रगत बग्ने समस्या) ।

Marks: 2

8. Read the following passage…
Suggest two actions that you—as a student or local citizen—can take to help preserve Nepal’s wildlife and their habitats.
(नेपालका वन्यजन्तु र तिनका वासस्थान संरक्षण गर्न विद्यार्थी वा स्थानीय नागरिकको रूपमा तपाईंले अपनाउन सक्ने कुनै दुई उपाय बताउनुहोस् ।)

उत्तर (Answer):

English:

Strict prohibition of poaching and illegal trade of animal parts.
Reduction of plastic pollution and protection of natural habitats.

Nepali:

चोरी शिकारी र अवैध व्यापारलाई कडाइका साथ नियन्त्रण गर्ने ।
प्राकृतिक वासस्थानको संरक्षण र प्लास्टिक प्रदूषण नियन्त्रण गर्ने ।

Marks: 2

9. Study the figure and use the given information to answer the question.
(तलको चित्र हेरेर दिइएको मापन अनुसार सोधिएका प्रश्नहरुको उत्तर लेख्नुहोस् ।)

उत्तर (Answer):

(a) Calculate the pressure transmitted through the liquid.
(तरल पदार्थमार्फत प्रसारित हुने दाब गणना गर्नुहोस् ।)

Pressure = $\frac{Force}{Area} = \frac{150N}{0.02m^2} = 7500 Pa$

(b) Determine the load that can be lifted by the large piston.
(ठूलो पिस्टनले उठाउन सक्ने तौल निकाल्नुहोस् ।)

Load = $Pressure \times Area = 7500 Pa \times 0.12m^2 = 900 N$

Marks: 1 + 1

10. When 15kg of cold water is mixed with 5kg of boiled water at $100^{\circ}C$, the final temperature becomes $36.25^{\circ}C$. Calculate the initial temperature of the cold water.
(15kg चिसो पानी र 5kg उम्लेको ($100^{\circ}C$ तापक्रमको) पानीसँग मिसाउँदा मिसाएको पानीको तापक्रम $36.25^{\circ}C$ भएछ भने चिसो पानीको तापक्रम निकाल्नुहोस् ।)

उत्तर (Answer):

Using Principle of Calorimetry: Heat Lost = Heat Gained

$m_1 s (t_1 – t) = m_2 s (t – t_2)$

$5 \times (100 – 36.25) = 15 \times (36.25 – T_{initial})$

$5 \times 63.75 = 15 \times (36.25 – T)$

$318.75 = 543.75 – 15T$

$15T = 543.75 – 318.75$

$15T = 225$

$T = 15^{\circ}C$

Answer: Initial temperature of cold water = $15^{\circ}C$

Marks: 2

11. Sameer cannot see the letters written on the board properly from the last bench. Which type of lens do you suggest to him for the remedy of his problem and why?
(समीर पछिल्लो बेन्चबाट बोर्डमा लेखिएका अक्षरहरू स्पष्ट देख्न सक्दैन । उनको आँखाको कमजोरी हटाउँनका लागि कुन प्रकारको लेन्स सिफारिस गर्नुहुन्छ ? कारण सहित लेख्नुहोस् ।)

उत्तर (Answer):

English: The defect is Myopia (Short-sightedness). A Concave lens is used to correct it because it diverges the incoming light rays before they enter the eye, shifting the image back onto the retina.

Nepali: यो अदूर दृष्टि (Myopia) हो । यसलाई सच्याउन कन्केभ लेन्स (Concave lens) प्रयोग गरिन्छ किनभने यसले प्रकाशका किरणहरूलाई विकेन्द्रित (diverge) गर्छ र प्रतिबिम्ब रेटिनामा बनाउँछ ।

Marks: 2

12. Study the given part of the periodic table and answer the following questions:
(तल दिइएको पिरियोडिक तालिका अध्ययन गर्नुहोस्, जसमा केही तत्वहरू देखाइएका छन्, र सोसँग सम्बन्धित प्रश्नहरूको उत्तर दिनुहोस्:)

उत्तर (Answer):

(a) On what basis are these elements arranged?
(तत्वहरू के को आधारमा मिलाइएका छन् ?)

Answer: Increasing atomic number.

(b) Which element has the smallest atomic radius? Give reason.
(कुन तत्वको परमाणविक अर्धव्यास सबैभन्दा सानो हुन्छ ? कारण सहित लेख्नुहोस् ।)

Answer: Argon (Ar) has the smallest atomic radius because atomic radius decreases as we move from left to right across a period due to increased effective nuclear charge.

Marks: 1 + 1

13. Two chemical reactions are given below.
(तल दुई रासायनिक अभिक्रियाहरू दिइएका छन् ।)
i) $CaCO_{3} \rightarrow CaO + CO_{2}$
ii) $HCl + NaOH \rightarrow NaCl + H_{2}O$

उत्तर (Answer):

(a) Write any two differences between equation (i) and (ii).
(रासायिनक प्रतिक्रिया (i) र (ii) बीचका कुनै दुई भिन्नताहरू लेख्नुहोस् ।)

English:

Equation (i) is a Decomposition reaction (breaks into simpler substances), while Equation (ii) is a Neutralization reaction (acid + base → salt + water).
Equation (i) requires heat, while Equation (ii) occurs at room temperature.

Nepali:

प्रतिक्रिया (i) विच्छेदन (Decomposition) प्रतिक्रिया हो भने (ii) उदासीनीकरण (Neutralization) प्रतिक्रिया हो ।
प्रतिक्रिया (i) लाई ताप चाहिन्छ भने (ii) सामान्य तापक्रममा हुन्छ ।

Marks: 2

14. List out the stages of metallurgy.
(धातु प्रशोधनका चरणहरू सूचीबद्ध गर्नुहोस् ।)

उत्तर (Answer):

English:

Concentration of Ore (धाउको गाढाकरण)
Roasting / Calcination (रोस्टिङ / क्याल्सिनेसन)
Reduction (न्यूनिकरण)
Refining / Purification (शुद्धिकरण)

Marks: 2

15. Hydrocarbons of the alkane series are commonly called paraffins.
(एल्केन श्रेणीका हाइड्रोकार्बनहरू सामान्यतया प्याराफिन भनिन्छ ।)

उत्तर (Answer):

(a) Why are they classified as paraffins?
(किन तिनीहरूलाई प्याराफिनको रूपमा वर्गीकृत गरिन्छ ?)

Answer: Because they are less reactive (have little affinity to react with other substances).

(b) Write one application of the alkane.
(एल्केनको एउटा उपयोगिता लेख्नुहोस् ।)

Answer: If $n=2$, the compound is Ethane ($C_2H_6$). It is used as a fuel or component of LPG.

Marks: 1 + 1

16. “Overuse of pesticides causes serious health problems.” Support this statement with two suitable arguments.
(“कीटनाशकको अत्यधिक प्रयोगले गम्भीर स्वास्थ्य समस्याहरू उत्पन्न गर्छ ।” यस कथनलाई कुनै दुई उपयुक्त तर्कद्वारा समर्थन गर्नुहोस् ।)

उत्तर (Answer):

English:

Excessive pesticides leave residues in food causing diseases in humans (cancer, nerve damage).
They kill beneficial insects and pollute soil and water sources, affecting the entire ecosystem.

Nepali:

अत्यधिक विषादीले मानव स्वास्थ्यमा गम्भीर असर (जस्तै क्यान्सर) निम्त्याउँछ ।
यसले फाइदाजनक कीराहरू मार्छ र माटो तथा पानी प्रदूषण गर्छ ।

Marks: 2

Section ‘D’: Long Answer Questions (7 × 4 = 28)

17. Study the given figure and answer the questions given below:
(दिइएको चित्र अध्ययन गरी तलका प्रश्नहरूको उत्तर दिनुहोस्:)

उत्तर (Answer):

(a) Write any two differences between broadband and baseband.
(ब्रडव्यान्ड र बेसव्यान्ड बीचका कुनै दुईवटा भिन्नताहरू लेख्नुहोस् ।)

English:

Broadband allows multiple signals to be sent simultaneously (multiplexing), whereas Baseband uses the entire bandwidth for a single signal.
Broadband supports high bandwidth for long-distance communication, while Baseband has low bandwidth suitable for short distances.

Nepali:

ब्रोडब्यान्डले धेरै सिग्नल एकैपटक पठाउँछ भने बेसब्यान्डले एउटा मात्र सिग्नल पठाउँछ ।
ब्रोडब्यान्ड लामो दुरीको सञ्चारको लागि उपयुक्त हुन्छ भने बेसब्यान्ड छोटो दुरीको लागि ।

(b) Write down an advantage of the above-mentioned communication system.
(माथि उल्लेखित सञ्चार प्रणालीको कुनै एउटा फाइदा लेख्नुहोस् ।)

English: High speed data transmission and suitability for long-distance communication.

Nepali: उच्च गतिमा डाटा सञ्चार र लामो दुरीको लागि उपयुक्त ।

(c) Differentiate between the above-mentioned communication with analogue communication.
(माथि उल्लेखित सञ्चार प्रणाली र एनालग सञ्चारबीच भिन्नता देखाउनुहोस् ।)

English: Digital signals (as shown) are discrete (0s and 1s) and less affected by noise, while analogue signals are continuous and more prone to noise distortion.

Nepali: डिजिटल सिग्नलमा ‘न्वाइज’ (noise) को असर कम हुन्छ र प्रशोधन गर्न सजिलो हुन्छ भने एनालग सिग्नलमा न्वाइजको असर धेरै हुन्छ ।

Marks: 2 + 1 + 1

18. Answer the following questions based on the given diagram.
(दिइएको चित्रका आधारमा तलका प्रश्नहरूको उत्तर दिनुहोस्:)

उत्तर (Answer):

(a) Write the name of the process shown in the diagram.
(चित्रमा देखाइएको प्रक्रियाको नाम लेख्नुहोस् ।)

English: IVF (In Vitro Fertilization).

Nepali: आई.भी.एफ (IVF) वा टेस्ट ट्युब बेबी प्रक्रिया ।

(b) What do A and B represent?
(A र B ले के जनाउँछन् ?)

English: A = Sperm (male gamete), B = Ovum/Egg (female gamete).

Nepali: A = शुक्रकीट, B = डिम्ब ।

English:

Advantage: Helps infertile couples to have children.
Disadvantage: It is expensive and technically complex with lower success rates.

Nepali:

फाइदा: निःसन्तान दम्पतीका लागि वरदान हो ।
बेफाइदा: यो महँगो र जटिल प्रविधि हो ।

Marks: 1 + 1 + 2

19. Define blood pressure. List out any three symptoms of high blood pressure.
(उच्च रक्तचापको परिभाषा लेख्नुहोस् । उच्च रक्तचापका कुनै तीन लक्षणहरू लेख्नुहोस् ।)

उत्तर (Answer):

Definition of Blood Pressure:
(रक्तचापको परिभाषा:)

English: The pressure exerted by the circulating blood against the walls of the arteries is called blood pressure.

Nepali: रगतले धमनीको भित्तामा दिने चापलाई रक्तचाप भनिन्छ ।

Symptoms of High Blood Pressure (Hypertension):
(उच्च रक्तचापका लक्षणहरू:)

English:

Severe headache (टाउको दुख्ने)
Nosebleed (नाकबाट रगत बग्ने)
Blurred vision (धमिलो देखिने)

Nepali:

टाउको दुख्ने
नाकबाट रगत आउने
आँखा धमिलो हुने

Marks: 1 + 3

20. A science teacher drops a small ball from the top of a tall tower. At the same moment, she asks another teacher to throw a second ball vertically upward from the bottom of the tower with a speed of $20 m/s$. Students observe that both balls meet at the same point after 2 seconds.
(एक विज्ञान शिक्षकले अग्लो टावरको टुप्पोबाट एउटा सानो बल खसाल्छिन् । त्यही समयमा उनले अर्को शिक्षकलाई टावरको तलबाट $20 m/s$ वेगले अर्को बल ठाडो माथि फ्याँक्न लगाउँछिन् । विद्यार्थीहरूले दुवै बल २ सेकेन्डपछि एउटै बिन्दुमा भेटिएको अवलोकन गर्छन् ।)

उत्तर (Answer):

(a) Calculate the height of the tower.
(टावरको उचाइ गणना गर्नुहोस् ।)

Let height of tower = $h$

For ball dropped from top (free fall): distance covered in 2s = $\frac{1}{2}gt^2 = \frac{1}{2} \times 9.8 \times 2^2 = 19.6m$

For ball thrown upward: distance covered = $ut – \frac{1}{2}gt^2 = 20 \times 2 – \frac{1}{2} \times 9.8 \times 4 = 40 – 19.6 = 20.4m$

Total height $h$ = distance covered by first ball + distance covered by second ball = $19.6 + 20.4 = 40m$

Height of tower = 40m

(b) What would be the apparent weight of the falling ball at that instant? Give a reason.
(सो क्षणमा खसिरहेको बलको आभासीय तौल कति हुन्छ ? कारणसहित लेख्नुहोस् ।)

English: The apparent weight of a freely falling body is zero ($0$ N) because reaction force $R = m(g-a)$, and in free fall $a=g$, so $R=0$.

Nepali: स्वतन्त्र खसाइमा रहेको वस्तुको तौल (Apparent weight) शून्य हुन्छ किनभने प्रतिक्रिया बल $R = m(g-a)$ हुन्छ र स्वतन्त्र खसाइमा $a=g$ हुन्छ, त्यसैले $R=0$ ।

Marks: 2 + 2

21. A person saw water on the road while driving on a coal-tarred road on a very hot day. But he did not find water when he reached that place.
(एक व्यक्तिले अत्यधिक गर्मी भएको दिनमा पिचरोडमा गाडी चलाउँदा सडकमा पानी देखे जस्तो अनुभव गरे तर जव उनी त्यो स्थानमा पुगेपछि पानी भेटिएन ।)

उत्तर (Answer):

(a) What is this condition called?
(यस अवस्थालाई के भनिन्छ ?)

English: Mirage.

Nepali: मृगमरीचिका (Mirage) ।

(b) What is the main cause of this condition?
(यस अवस्थाको मुख्य कारण के हो ?)

English: Total Internal Reflection (TIR) of light due to refraction through air layers of different densities/temperatures.

Nepali: प्रकाशको पूर्ण आन्तरिक परावर्तन (Total Internal Reflection) ।

(c) Write any two conditions required for this process to occur.
(यो प्रक्रिया हुन आवश्यक पर्ने कुनै दुई अवस्थाहरू लेख्नुहोस् ।)

English:

The ground must be very hot (creating layers of varying optical density).
The angle of incidence must exceed the critical angle.

Nepali:

जमिन तातो हुनुपर्छ (विभिन्न घनत्वका हावाका तहहरू बन्नुपर्छ) ।
आपतित कोण क्रिटिकल कोणभन्दा बढी हुनुपर्छ ।

Marks: 1 + 1 + 2

22. Study the following figure.
(दिइएको चित्र अध्ययन गर्नुहोस् ।)

उत्तर (Answer):

(a) Where is this type of transformer used?
(यस प्रकारको ट्रान्सफर्मर कहाँ प्रयोग गरिन्छ ?)

English: To step-up or step-down AC voltage for efficient power transmission and distribution.

Nepali: भोल्टेज बढाउन वा घटाउन (AC करेन्टमा) विद्युत् सञ्चार र वितरणमा ।

(b) If there are 1000 primary turns and 300 secondary turns, calculate the output voltage when connected to 220V AC.
(यदि प्राईमरी क्वाईलको सङ्ख्या 1000 र सेकेण्डरी क्वाईलको सङ्ख्या 300 छन् भने, 220V AC भोल्टको एसीमा ट्रान्सफर्मर जोड्दा हुने सेकेण्डरी भोल्टेज निकाल्नुहोस् ।)

Using transformer formula: $\frac{V_p}{V_s} = \frac{N_p}{N_s}$

$\frac{220}{V_s} = \frac{1000}{300}$

$V_s = \frac{220 \times 300}{1000} = 66V$

Output voltage = 66V

English: The core is laminated (made of thin sheets) to reduce energy loss caused by Eddy Currents.

Nepali: ‘एडी करेन्ट’ (Eddy Current) बाट हुने शक्ति ह्रास कम गर्न कोरलाई लेमिनेसन (laminated) गरिएको हुन्छ ।

Marks: 1 + 2 + 1

23. Study the given figure alongside and answer the following questions:
(दिइएको चित्र अध्ययन गरी तलका प्रश्नहरूको उत्तर दिनुहोस्:)

उत्तर (Answer):

(a) Which gas is collected in the gas jar?
(ग्याँस जारमा कुन ग्यास सङ्कलन गरिएको छ ?)

English: Ammonia gas ($NH_3$).

Nepali: एमोनिया ग्यास ($NH_3$) ।

(b) Why is the tank X used?
(टयाङ्गी X किन प्रयोग गरिएको हो ?)

English: This is a Lime Tower containing Quick lime ($CaO$). It is used to dry the ammonia gas (absorb moisture).

Nepali: यो लाइम टावर (क्याल्सियम अक्साइड) हो, जसले ग्यासलाई सुक्खा बनाउँछ (ओसिलोपना हटाउँछ) ।

English: It turns damp Red Litmus paper into Blue, indicating it is basic in nature. It also has a pungent smell.

Nepali: यसले रातो लिटमसलाई नीलो बनाउँछ (क्षारीय गुण) र तीखो गन्ध आउँछ ।

(d) Mention a use of the prepared gas for the agricultural sector.
(कृषि क्षेत्रमा उक्त ग्यासको एउटा प्रयोग लेख्नुहोस् ।)

English: Used to manufacture chemical fertilizers (like Urea) to enrich soil.

Nepali: रासायनिक मल (युरिया) बनाउन प्रयोग गरिन्छ ।

Marks: 1 + 1 + 1 + 1

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English Nepali Social Studies Compulsory Math Science Account Economics Optional Math

Table of Contents

Question Paper Preview

Section ‘A’: Multiple Choice Questions (10 × 1 = 10)

Section ‘B’: Very Short Answer Questions (9 × 1 = 9)

Section ‘C’: Short Answer Questions (14 × 2 = 28)

Section ‘D’: Long Answer Questions (7 × 4 = 28)

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