POINTS TO REMEMBER:
1) ECOLOGY – The study of the interaction of living organisms with each other and their surroundings is called ecology. 2) ENVIRONMENT – Everything that surrounds organisms and influences its life. a) Biotic components of environment --- The living organisms .e.g. Plants and animals. b) Abiotic components of environment --- The nonliving components like water, air, light, etc. It is the sum total of all external conditions and influences that affect the life and the development of organisms i.e.,it includes all the biotic and abiotic factors. 3) ECOSYSTEM – All interacting organisms in an area together with the nonliving constituents of environment. (Functional unit of an environment) Functions of ecosystem:- a) Flow of energy b) Cycling of nutrients(bio-geo chemical cycles). 4) PRODUCERS --- They make the energy from sunlight available to the rest of the ecosystem. 5) CONSUMERS --- Animals can not manufacture their own food. They are called consumers. 6) BIODEGRABLE ---- Substances that are broken down by the action of bacteria or other saprophytes. e. g. – Paper. 7) NONBIODEGRABLE --- Substances that are not broken down by the action of bacteria or saprophytes. e. g. Plastic. 8) FOOD CHAIN ---- The process of one organism eating the other. GRASS -> GRASSHOPPER -> FROG -> SNAKE Importance of food chain 1.It helps in transfer of food energy from one organism to another. 2.It is a pathway for the flow of energy. 3. It helps in understanding the interdependence amongst different organisms. Trophic levels are the various steps in the food chain . Producers --- first trophic level Herbivores --- second trophic levels Carnivores --- third trophic level Top carnivores --- fourth trophic level 9) FOODWEB ----- It is a network of food links between populations in a community. 10) FLOW OF ENERGY -Ten percent law Energy available at each successive trophic level is 10 % of the previous level. (Lindeman 1942) The law states that, “ only a 10 % amount of the total available energy is transferred from one trophic level to the next. The rest 90% of energy is used up or lost to the surrounding.” 11) BIOLOGICAL MAGNIFICATION --- Progressive accumulation of nonbiodegradable waste at various trophic levels of food chain. 12. Differences between food chain & food web Food chain 1. The process of eating & being eaten to transfer food energy. 2. It forms a part of food web. 3. It has limited populations. Food web 1. It is a system of interconnected food chains. 2. It contains many food chains. 3. It has several populations of different species. 13. HOW DO OUR ACTIVITIES AFFECT THE ENVIRONMENT? Two major problems:- a) Depletion of ozone layer b) Disposal of wasteGood ozone and bad ozone The thick blanket of ozone layer in the atmosphere which forms a protective cover & prevents UV radiation from reaching the earth‘s surface. This is called good ozone and is found in the stratosphere. Ozone when present in the troposphere act as a pollutant . This harmful ozone is called bad ozone. 14. Depletion of ozone layer : The ozone layer protects all the organisms from the harmful ultra violet rays. Ozone depleting substances: CFCs, N2O, CH4 , CCl4 These chlorine containing compounds are used in: Aerosols, solvents, refrigerants and fire extinguishers. Ozone hole developed over Antartica. 15. Effects of ozone depletion on human health- Due to depletion of ozone layer UV radiations reaches the earth and cause: i) skin cancer ii) increased chances of cataract iii) suppression of immune system . Managing the garbage we produce 16. Reasons for large production of garbage i) Improvement in life style ii) Changes in attitude (more things become disposable) iii) Population explosion iv) Changes in packaging(non -biodegradable) More topics to read FORMATIVE ASSIGNMENT - III 10th Our Environment 10th Our Environment HIGHER ORDER THINKIN SKILLS (HOTS) QUESTIONS 10th physics Chapter - 15 Our Environment POINTS TO REMEMBER
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Q1. Find the co-ordinates of a point which divide the segment AB in the ration 3:5 internally, where A(4 , –1 ) and B(–2, 4).
Q2. Find the co-ordinates of points of trisection of the segment joining points (4, –8) and (7, 4). Q3. In what ratio does the point (3, 12) divide line segment joining the points (1, 4) and (4, 16)? Q4. Determine the ratio in which the line 3x + y – 9 = 0 divides the segment joining the points (1, 3) and (2, 7). Q5. Find the point which represent 3/4 of the distance from (3, 2) and (–5, 6). Q6. (a) In what ratio the line segment joining the points (–2, –3) and (3, 7) divided by y-axis? Also, find the co-ordinates of the point of division. (b) In what ratio the line segment joining the points (2, –3) and (5, 6) divided by y-axis? Also, find the co-ordinates of the point of division. Q7. If A (5, –1), B (–3 , –2) and C (–1, 8) are the vertices of ∆ABC, find length of median through A And also find the co-ordinates of the centroid. Q8. Find the co-ordinates of vertices of triangle, if the co-ordinates of mid points of sides of the Triangle are: (a) (3, 2) , (4, 4) and (1, 3) (b) (3, 4) , (4, 1) and (2, 0) Q9. Find co-ordinate of centroid of triangle whose vertices are: (a) (–2, 1) , (–3, 4) and (8, –11) (b) (–2, 4) , (7, –3) and ( 4, 5) Q10. Find the third vertex of triangle, if its two vertices are (–4, 1) and (5, 2) and its centroid is (1, 3). Q11.Three consecutive vertices of a parallelogram are (–2, –1), (1, 0) and (4, 3). Find its fourth vertex. Q12. Find the co-ordinates of points which divide the line segment joining the points (–4, 0) and (0, 6) in four equal parts. Q13.Find the value of x such that PQ = QR, where the co-ordinates of P, Q and R are (6, –1), ( 1,3) And (x, 8). Q14. Find the point on x-axis which is equidistant from points (7, 6) and (–3, 4). Q15. A line segment joining the points (3, –4) and (1, 2) is trisected at the points P and Q. If the co-ordinates of P and Q are (p, –2) and (5/3, q) respectively. Find p and q. Q16. Determine ratio in which the point P(m, 6) divides the join of A(–4, 3) and B(2, 8). Also find m. Q17. Prove that the four points whose co-ordinates are (0, 5), (–2, –2), ( 5, 0) and (7, 7) form rhombus. Q18.Prove that (–5, 6), (3, 0) and (9, 8) are the vertices of an isosceles right-angled triangle. Q19. The co-ordinates of the mid points of the sides of a triangle are (1, 1) , (2, –3) and (3, 4). Find The co-ordinates of its centroid. Q20.If two vertices of an equilateral triangle are (0, 0) , ( 3,√3 ), find the third vertex. Q21. Find the lengths of the medians of a ∆ABC whose vertices are A (7, –3) , B (5, 3) and C (3, –1). Q22. The line joining the points (2, 1) and (5, 8) is trisected at the points P and Q. If point P lies on the line 2x – y + k = 0, find the value of k. Q23. If the point (x, y) is equidistant from the points (a+ b , b –a) and (a – b, a + b), prove that bx = ay. Answers Ans 1.(7/4, 7/8) Ans2. (5, –4) and (6, 0) Ans3. 2:1 Ans4. 3:4 Ans5.( –3, 5) Ans6. (a) 2:3 and (0, 1)(b) 1: 2 Ans7.65 and (1/3, 5/3) Ans8. (a) (0, 1) , (6, 3) and ( 2, 5)(b) (1,3) , (5, 5) and ( 3, –3) Ans9.(a) (1, –2)(b) (3, 2) Ans10. (–1, 3) Ans11. (1, 2) Ans12. (–3, 3/2) , (–2, 3) and (–1, 9/2) Ans13. 5 or –3 Ans14. 3 Ans15. p = 7 /3 and q = 0 Ans16. 3:2 , m =–2/5 Ans19. (2, 2/3) Ans20.(0,2√3 ) or (3, -√3) Ans21. 5, 5,√10 Ans 22. –8 Q1 A ladder 15 m long just reaches the top of a vertical wall. If the ladder makes an angle of60°with the wall, find the height of the wall. (7.5 √3 )
Q 2 A pole 12 m high casts a shadow 4 √3 m long on the ground. Find the angle of elevation (60°) Q 3 The angle of elevation of the top of a tower from a point on the ground is 30° if on walking 30m towards the tower, the angle of elevation becomes 60°.Find the height of the tower.(15√3 ) Q 4 An observer 1.5m tall is 20.5m away from a tower 22m high. Determine the angle of elevation of the top of the tower from the eye of the observer. (45°) Q 5 An aero plane when flying at a height of 5000m from the ground passes vertically above another aero plane at an instant when the angles of the elevation of the two planes from the same point on the ground are 60° and 45° respectively. Find the vertical distance between the aero planes at the instant. (2116.5m) Read more » Download More Test paper 10th_heights_and_distances_test_paper_1 Download File 10th_application_of_trigonometry _Test paper -2 Download File |
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