Science Question


 
                                               2074
Subject: Science                                                             Full Mark:75
Class: VIII                  Time: 2:15 Hrs.                       Pass Mark:  30

Candidates are required to give their answers according to the given  instruction.
Attempt all the questions:  
;a} k|Zgx? clgjfo{ 5g\ .

SET B          GROUP A (PHYSICS)
1. a. What is meant by weight of an object? On what two factors does it depend?                                1+1
            वस्तुको तौल भन्नाले के बुझिन्छ ? यो कुन दुई कुरामा भर पर्छ ?
b. The unit of power is derived unit, why? Convert 1g/cm3 into SI unit.
सामर्थ्यको एकाइ तत्जन्य एकाइ हो, किन ? 1g/cm3 लाई एस.आइ. एकाइमा परिवर्तन गर्नुहोस् ।                                             1+2
2. a. What is average velocity? A car is moving in east direction with 20m/s velocity and another towards west with velocity 72km/hr. What is the relative velocity between them?                                           1+2
औसत गति भनेको के हो ? एउटा कार 20m/s को गतिले पूर्वतिर गइरहेको छ र अर्को कार 72km/hr को गतिले पश्चिमतिर गइरहेको छ भने ति दुई कारबिचको सापेक्षित गति कति हुन्छ ?
b. Explain an example to show that distance never be zero but displacement might be zero.                               2
दुरी शुन्य नहुने तर स्थानान्तरण शुन्य हुने कुनै एक उदाहरणलाई व्याख्या गर्नुहोस् ।
3. a. What is work input? No machine is 100% efficient, why?                                                                           1+1.5
लागत कार्य भनेको के हो ? कुनै पनि यन्त्रको कार्यक्षमता 100% हुँदैन, किन?                                                   
b. Write down the working principle of lever. Find out the effort in the given figure.                                                                                          1+1.5
उत्तोलकको कार्यगत सिद्दान्त लेखनुहोस् । दिइएको चित्रमा इफोर्ट पत्ता लगाउनुहोस ।
3. a.   Define unit. The mass of substance is 5kg. What does it mean?                                                  1+1
            एकाई भनेको के हो ? कुनै वस्तुको पिण्ड 5kg छ भन्नाले के बुझिन्छ ?
b. What is reference point? Distinguish between acceleration and retardation.                      1+2
            सापेक्षित विन्दु भनेको के हो ? प्रवेग र गतिह्रासबिच फरक छुट्याउनुहोस् ।
4. a.   Define velocity ratio. It is easier to lift the load in wheel barrow if it is shifted towards the wheel, why? 1+2
गरि अनुपातलाई परिभाषित गर्नुहोस् । एक पाङ्ग्रे ठेलागाडामा लोडलाई जति पांग्रातिर सारियो उति नै उचाल्न सजिलो हुन्छ, किन ?
b. Prove the relation v2 = u2 + 2as, where symbols have their usual meaning.                                                      2
          v2 = u2 + 2as हुन्छ भनि प्रमाणित गर्नुहोस् ।    

Group B (CHEMISTRY)
5. a.   An atom is electrically neutral, why? Draw an atomic structure of chlorine atom.                       1+1.5
परमाणुहरु विधुतिय रुपमा तटस्थ हुन्छन्, किन ? क्लोरिन परमाणुको आणविक संरचना देखाउनुहोस ।
b. If the atomic number of Argon is 18 and atomic weight is 40 then calculate number of p, n, and e of this atom.                                                                    2.5
यदि आर्गनको पारमणविक संख्या 18 र पारमणविक भर 40 छ भने प्रोटोन, न्युट्रोन र इलेक्ट्रोनको संख्या पत्ता लगाउनुहोस ।
6. a.   Calculate the molecular weight of Calcium Carbonate.    2
            क्याल्सियम कार्बोनेटको आणविक भार निकाल्नुहोस् ।
b. How many electrons are in 1 Coulomb charge? State Mendeleev’s law and write its two defects.  1+1+1
1 कोलम्ब चार्जमा कति इलेक्ट्रोनहरु हुन्छन् ? मेंदेलिभको पेरियोडिक नियम लेखि यस तालिकाको कुनै दुइ त्रुटीहरु लेखनुहोस् ।
7. a. Distinguish between electron and neutron.   2
            इलेक्ट्रोन र न्युट्रोनबिच फरक छुट्याउनुहोस् ।
b. Define chemical reaction. Convert the given word equation into balanced chemical equation.           1+2
Potassium Chlorate   heat   Potassium chloride+oxygen

GROUP C (BIOLOGY)
8. a.   Write any two reasons for the modification of different parts of plants.                                                 2
विरुवाको विभिन्न अंगहरु किन रुपान्तरित हुन्छन् ? कुनै दुई कारण लेखनुहोस् ।
b. Describe an activity to show the suitable condition for germination seed. (With diagram)                      3
विउको अंकुरणलाई चाहिने उपयुक्त अवस्था देखाउने एउटा क्रियाकलाप सचित्र व्याख्या गर्नुहोस् ।
9. a. What is fertilization? Write any four ways of dispersal of seed.                                                             1+2
गर्भाधारण भनेको के हो? विउ छरिने कुनै चार विधिहरुको नाम लेखनुहोस्।
b. Who introduced bacteria for the first time? What is meant by bacteriophage virus?                     1+1
ब्याक्टेरियालाई सर्वप्रथम कसले पत्ता लगाएका हुन् ? ब्याक्टेरियोफेज भाइरस भन्नाले के बुझिन्छ ?
10. a.           What is hyphae? Write any two characteristics of fungi.
                                                                             1+2
            हाइफी भनेको के हो ? फंगाइको कुनै दुई विशेषताहरु लेखनुहोस् ।
     b. What is micropyle? Write its function.                     1+1
            माइक्रोपाइल भन्नाले के बुझिन्छ ? यसको एउटा कार्य लेखनुहोस् ।


GROUP D (GEOLOGY and ASTRONOMY)
11. a. Describe the hypothesis proposed by Jeans and Jeffrey. 2
            जिन्स र जेफ्रेद्वारा प्रतिपादन गरिएको परिकल्पनाको बारेमा लेखनुहोस् ।
b. What is meant by sidereal month? Distinguish between summer and winter season.                            1+2
            नक्षत्रमास भनेको के हो ? ग्रीष्म र शिशिर ऋतुबीच फरक छुट्याउनुहोस् ।

GROUP E (ENVIRONMENTAL SCIENCE)
12. a.           Write any two differences between species diversity and genetic diversity.                                             2
प्रजाति विविधता र वंशाणुगत विविधताबिच कुनै दुईओटा फरक लेखनुहोस् ।
b. Write any six efforts being paid globally for sustainable development.                                          3
विश्वको सन्दर्भमा दिगो विकासका लागि गरिएका कुनै छ प्रयासहरु वुदागत रुपमा लेखनुहोस् ।
13. a. What is meant by limitation of development? Clarify it. 2
            विकासको सिमा निर्धारण भन्नाले के बुझिन्छ ? प्रष्ट पार्नुहोस् ।
     b. Write the importance of sustainable development in points.                                                        3
            दिगो विकासको महत्वलाई वुदागत रुपमा प्रकाश पार्नुहोस् ।
14. a.           Which unit transfers heredity character from parents to offspring?
          i. Cell (कोष)                           ii. Blood (रगत)
          iii. Gene (वंशाणु)                    iv. Tissue (तन्तु)
            Write in short about ecosystem diversity.                  1+2
            पारिस्थितिक प्रणाली विविधताको बारेमा छोटकरीमा लेखनुहोस् ।
b. When did world communication of environment and development form? Define sustainable development according to it.                                            1+1
वातावारण र विकास सम्बन्धी विश्व आयोगको गठन कहिले गरियो ? यो आयोगले दिएको दिगो विकासको परिभाषा लेखनुहोस् ।
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