Tiêu đề VIII Science MS.pdf ✅

KENDRIYA VIDYALAYA SANGATHAN, LUCKNOW REGION MID TERM EXAMINATION – 2023 – 24 CLASS 8TH – SCIENCE – SET 1 – MARKING SCHEME Q NO. CORRECT ANSWER MARKS 1. (b) cow-dung OR (c) Both a & b 1 2. (b) only inside the cells of the host organisms 1 3. (c) biogas 1 4. (d) sunlight 1 5. (a) outermost zone 1 6. (d) all the above conditions are necessary 1 7. (d) both (a) and (b) 1 8. (a) forest fires 1 9. (b) increase pressure OR (c) gravitational force 1 10. (a) place it on a trolley 1 11. Rhizobium Fixation of nitrogen in pulse plant 1 1 12. A B i) Lactobacillus setting of curd ii) Yeast baking of bread iii) A protozoan causing malaria iv) A virus causing AIDS 1⁄2 x4 =2 13. a) Liquids exerts equal pressure in all direction at the same depth. b) The stream of water that will come out of this (X) hole will have less pressure 1 1 14. Petroleum conservation research association. Its advices are: Drive at a constant & moderate speed as far as possible. Ensure correct tyre pressure (or any two advice) OR 1. Coal & petroleum are exhaustible natural resources and these will last only a few hundred years. 2. Burning of these fuels cause air pollution. 1 1 1+1 =2
15. A. Gravitational force - non-contact force B. Muscular force- contact force 1/2 + 1/2 =1 1 16.  False  true 1+1 17. i) Air does not enter the chimney from below so complete combustion can’t occur hence flame flickers and gives smoke. ii) Air is not available so flame goes off. OR Diagram of a candle flame with four labelling. 1 + 1 = 2 2 18. Two examples each of situations that shows friction is a friend two examples each of situations that shows friction is foe. 1/2+1/2=1 1/2 + 1⁄2= 1 19. Sportsmen use shoes with spikes, as it increases friction so sportsmen get firm grip of the ground. OR Streamlined shape minimizes fluid friction, this makes them lose less energy. 2 20. Red data book contains the record of endangered species. OR Endangered species are those which are facing the danger of extinction. 1+1 21. Comparison of manure and fertilizer (4 points). Manure is better – it is eco-friendly, improves soil texture and it enhances the water holding capacity. OR Explanation of weeding in agriculture any two methods of weeding. 1⁄2 x 4 =2 1⁄2 + 1⁄2 =1 1 2 22. Explanation of sprinkler system. Explanation of drip system OR Tool A – Hoe, used for removing weeds Tool B - Seed drill, used for sowing of seeds 1.5 1.5 1⁄2 + 1 =1.5 1⁄2 + 1 =1.5 23. For any three effects of force. OR Shoulder bags are provided with broad straps and not thin straps as larger the area of straps lesser will be the pressure. b) Definition of pressure pressure = force/ area on which it acts 3 1.5 1 0.5