{"id":33944,"date":"2019-10-25T17:11:54","date_gmt":"2019-10-25T11:41:54","guid":{"rendered":"https:\/\/www.cbselabs.com\/?p=33944"},"modified":"2021-09-18T15:15:48","modified_gmt":"2021-09-18T09:45:48","slug":"cbse-previous-year-question-papers-class-10-science-sa2-outside-delhi-2012","status":"publish","type":"post","link":"https:\/\/www.cbselabs.com\/cbse-previous-year-question-papers-class-10-science-sa2-outside-delhi-2012\/","title":{"rendered":"CBSE Previous Year Question Papers Class 10 Science SA2 Outside Delhi – 2012"},"content":{"rendered":"
Science<\/a>Maths<\/a>Sanskrit<\/a>English<\/a>Computer Science<\/a>Hindi<\/a>Social Science<\/a> GENERAL INSTRUCTIONS:<\/strong><\/span><\/p>\n SECTION A<\/strong><\/span> Question.2 State one function of iris in human eye.<\/strong> Question.3 What happens when higher energy ultraviolet radiations act on the oxygen at the higher level of the atmosphere?<\/strong> Question.4 In a food chain, if 10,000 joules of energy is available to the producer, how much energy will be available to the secondary consumer to transfer it to the tertiary consumer?<\/strong> Question.5 Choose from the following:<\/strong> Question.6 An element ‘X’ belongs to 3rd period and group 17 of the periodic table. State its<\/strong> Question.7(a) State the role of placenta in the development of embryo.<\/strong> Question.8 To construct ray diagram we use two light rays which are so chosen that it is easy to know their directions after reflection from the mirror. List these two rays and state the path of these rays after reflection. Use these rays to locate the image of an object placed between centre of curvature and focus of a concave mirror.<\/strong> Question.9 (a) Draw a labelled ray diagram to illustrate the dispersion of a narrow beam of white light when it passes through a glass prism.<\/strong> Question.10 A 4 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 24 cm. The distance of the object from the lens is 16 cm. Find the position, size and nature of the image formed, using the lens formula.<\/strong> Question.11 List three problems which arise due to construction of big dams. Suggest a solution for these problems.<\/strong> Question.12 List the products pf combustion of fossil fuels. What are their adverse effects on the environment?<\/strong> Question.13 What is meant by homologous series of organic compounds? Write the chemical formulae of two members of a homologous series and state which part determines the<\/strong><\/p>\n Answer.<\/strong> A homologous series is a group of organic compounds having similar structures and similar chemical properties in which the successive compounds differ by CH2<\/sub> group. Example: The general formula of. the homologous series of alkenes is where n is Question.14 Na, Mg and A1 are the elements having one, two and three valence electrons , . respectively. Which of these elements<\/strong><\/p>\n reactive? Justify your answer stating reason for each.<\/strong> Question.15 List and explain in brief three methods of contraception.<\/strong> Question.16 If we cross pure-bred tall (dominant) pea plant with pure-bred dwarf (recessive) pea plant we will get pea plants of \u00a0<\/sub>F1<\/sub> generation. If we now self-cross the pea plant of F1<\/sub> generation, then we obtain pea plants of \u00a0<\/sub>F2<\/sub> generation.<\/strong> Question.17 List in tabular form two distinguishing features between acquired traits and inherited traits, with one example of each.<\/strong> Question.18 How are fossils formed? Describe, in brief, two methods of determining the age of fossils.<\/strong> Question.19 Ethanol is one of the most important industrial chemicals. It is used in medicine, to synthesize many important compounds, it is an excellent solvent.<\/strong> (b) ‘Alcohol drinking should not be portrayed on media’ because young people and children are very much influenced by the media. Question.20 With the help of a ray diagram, state what is meant by refraction of light. State Snell’s law for refraction of light and also express it mathematically.<\/strong> Question.21 List the new Cartesian sign convention for reflection of light by spherical mirrors. Apply these conventions for calculating the focal length and nature of a spherical mirror which forms a 1\/3 times magnified virtual image of an object placed 18 cm in front of it.<\/strong> Question.22 What are hydrocarbons? Write the name and general formula of<\/strong> Question.23 Distinguish between unisexual and bisexual flowers giving one example of each. Draw a diagram showing the process of germination of pollen grains on stigma and label the following parts:<\/strong> Question.24 Draw a diagram of human female reproductive system and label the part<\/strong> SECTION B<\/strong><\/span> Question.26 On adding acetic acid to sodium hydrogen carbonate in a test tube, a student observes<\/strong> Question.27 Which one of the following are the correct observations about acetic acid?<\/strong> Question.28 A student has to determine the focal length of a concave mirror by obtaining the image of a distant object on a screen. For getting the best result he should focus<\/strong> Question.29 If you are to determine the focal length of a convex lens, you should have ,<\/strong> Question.30 Four students showed the following traces of the path of a ray of light passing through<\/strong> Question.31 The following figures illustrate binary fission in Amoeba in an incorrect sequence.<\/strong> Question.32 A student weighed some raisins and recorded the weight as V. She then soaked the raisins in distilled water. After about 2 hours she removed the raisins, wiped them dry and weighed again and recorded that as ‘y’. The percentage of water absorbed by raisins may be determined using the relationship<\/strong> Question.33 A chain of yeast cells forms because<\/strong> Question.34 What are cotyledons? How are the number of cotyledons different in gram seed and the maize (com) seed?<\/strong> Question.35 Why is emergent ray parallel to the incident ray, after the refraction of Incident ray through a glass slab?<\/strong> Question.36 When boilers of water are used for a very long time, then white layers get deposited on inside of these boilers? How can these white layers be removed?\u00a0<\/strong> Except for the following questions, all the remaining questions have been asked in Set-1.<\/strong> Question.2 State one function of pupil in human eye.<\/strong>
\nTime allowed: 3 hours \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Maximum marks: 90<\/strong><\/p>\n\n
\nabout 50 words each.<\/strong><\/li>\nSET I<\/strong><\/span><\/h3>\n
\nQuestion.1 Write the name and formula of the second member of the carbon compounds having functional group\u2014OH.<\/strong>
\n Answer.<\/strong> Second member of alcohol family \u2014 C2<\/sub>H5<\/sub>OH CH3<\/sub>-CH2<\/sub>-OH Ethanol<\/p>\n
\n Answer.<\/strong> Function of iris. Iris regulates the amount of light entering the eye by adjusting the size of the pupil.<\/p>\n
\n Answer.<\/strong> The high energy ultraviolet radiation (UV radiation) coming from the Sun splits oxygen
\ngas into free oxygen atoms
\n
\nThe free oxygen atoms thus produced react with an oxygen molecule to form ozone molecule
\n<\/p>\n
\n Answer.<\/strong>
\n
\n<\/p>\n
\n
\nAnswer.<\/strong>
\n<\/p>\n
\n (i) electronic configuration, (ii) valency. Justify your answer with reasoning.<\/strong>
\n Answer.<\/strong>
\n<\/p>\n
\n (b) What happens when the egg is not fertilised?<\/strong>
\n Answer.<\/strong>
\n(a) Role of placenta. After implantation, a disc like special tissue develops between the uterus wall and the embryo called placenta.
\nThe exchange of nutrients, oxygen and waste products between the embryo and the mother takes place through the placenta.
\n(b) If the egg does not get fertilised (due to non-availability of sperms in the female body) then the thick and soft inner lining of uterus along with the blood vessels and the dead egg comes out of the vagina in the form of bleeding called menstruation.<\/p>\n
\n Answer.<\/strong> Rays used and their path after reflection:
\n(i) A ray parallel to the principal axis after reflection this ray will pass through the principal focus in case of a concave mirror or appear to diverge from the principal focus in case of a convex mirror.
\n(ii)A ray passing through the centre of curvature of a concave mirror or directed in the direction of the centre of curvature of a convex mirror, after reflection, is reflected back along the same path.
\n<\/p>\n
\n (b) A star appears slightly higher (above) than its actual position in the sky. Illustrate it with the help of a labelled diagram.<\/strong>
\n Answer.<\/strong>
\n<\/p>\n
\n Answer.<\/strong>
\n<\/p>\n
\n Answer.<\/strong> Three problems that arise due to construction of big dams:<\/p>\n\n
\nSuggestions for these problems. All the people who are displaced from the dam site should be given adequate compensation by the Government for rehabilitation so as to start their life afresh.<\/li>\n<\/ol>\n
\n Answer.<\/strong> When fossil fuels are burnt, the products of combustion are\u2014carbon dioxide, water, sulphur dioxide and nitrogen oxides. If combustion takes place in an insufficient supply of air then carbon monoxide is produced. All these products are harmful and create some adverse effects on the environment.<\/p>\n\n
\n
\nthe number of carbon atoms.
\n1st member is CH4<\/sub>, 2nd member is C2<\/sub>H6<\/sub><\/p>\n\n
\n
\n Answer.<\/strong> Na, Mg and AI are the elements of same period where Na is the first, Mg is the second and A1 is the third member.<\/p>\n\n
\nshell. Due to large positive charge on the nucleus, the electrons are pulled in more close to the nucleus and the size of the atom decreases.<\/li>\n
\n Answer.<\/strong> Three different methods of contraception:<\/p>\n\n
\nOther contraceptive devices such as loop or the copper-T are placed in the uterus to prevent pregnancy.<\/li>\n<\/ol>\n
\n (a) What do the plants of F1<\/sub> generation look like?<\/strong>
\n (b) State the ratio of tall plants to dwarf plants in F2<\/sub> generation.<\/strong>
\n (c) State the type of plants not found in \u00a0<\/sub>F1<\/sub>, generation but appeared in \u00a0<\/sub>F2\u00a0<\/sub>generation, mentioning the reason for the same.<\/strong>
\n Answer.<\/strong>
\n(a) The plants of\u00a0<\/sub>F1<\/sub>generation are all Tall.
\n(b) Tall plants : Dwarf plants \u2014 3:1
\n(c) Dwarf plants: This is because irt \u00a0<\/sub>F2<\/sub> generation, Tall is a dominant trait whereas in \u00a0<\/sub>F2<\/sub>\u00a0generation, two copies of ‘tt’\/recessive traits made the plant dwarf.<\/p>\n
\n Answer.<\/strong>
\n<\/p>\n
\n Answer.<\/strong> When organisms (plants or animals) die, their bodies will decompose by the action of micro-organisms in the presence of oxygen, moisture, etc.
\nSometimes in the lack of such conditions (oxygen, moisture, etc.), their body does not decompose completely and is preserved as fossil with the passage of time in the rocks. In many cases the soft parts of the organism get decomposed and hard parts (like bones etc.) become fossil. Sometimes even the soft parts (like leaf etc.) remain preserved as fossils in the form of their impressions inside the rocks.
\nMethods to determine the age of fossils:<\/p>\n\n
\n However, inspite of its benefits it causes many social problems. If a person drinks alcohol regularly, he becomes an alcoholic. Alcohol is non-toxic but it produces physiological effects disturbing brain activity. These persons are also a threat to the lives of othets.<\/strong>
\n (a) Give three reasons in favour and three reasons against ‘alcohol-free world’.<\/strong>
\n (b) ‘Alcohol drinking should not be potrayed on media.’ Give valid reasons to justify.<\/strong>
\n (c) As a student what initiative would you take in the concern of “We should condemn<\/strong>
\n drinking alcohol\u201d.<\/strong>
\n Answer.<\/strong> (a) In favour of ‘Alcohol-free world’:<\/p>\n\n
\nsociety.<\/li>\n
\nAgainst ‘Alcohol-free world’:<\/li>\n
\n(c) Initiatives taken by a student to create awareness about drinking alcohol could be:<\/p>\n\n
\n The refractive index of air with respect to glass is 2\/3 and the refractive index of water with respect to air is 4\/3. If the speed of light in glass is 2×108<\/sup> m\/s, find the speed of light in (a) air, (b) water.<\/strong>
\n Answer.<\/strong> Refraction of light. The bending of light when it passes from one medium to another is called refraction of light.
\n
\n<\/p>\n
\n Answer.<\/strong>
\n<\/p>\n
\n (i) saturated hydro-carbons,<\/strong>
\n (ii) unsaturated hydrocarbons, and draw the structure of one hydrocarbon of each type. How can an unsaturated hydrocarbon be made saturated?<\/strong>
\n Answer.<\/strong>
\n
\n
\nOr<\/strong>
\n What are detergents chemically? List two merits and two demerits of using’detergents for cleansing. State the reason for the suitability of detergents for washing, even in the case of water having calcium and magnesium ions.<\/strong>
\n Answer.<\/strong> Detergents are generally ammonium of sulphonate salts of long chain carboxylic acids.
\nA detergent is the sodium salt of a long chain benzene sulphonic acid. A common detergent is sodium n-dodecyl benzene sulphonate.
\nDetergent can lather well even in hard water because they do not form insoluble calcium water. A detergent works by making the oil and grease particles of dirty clothes dissolve in water through the formation of miscelles.
\nMerits of using detergents. Detergents are strong cleansing agents. Detergents form foam even with hard water.
\nDemerits of using detergents. Detergents are non-biodegradable.<\/p>\n
\n (i) Female germ cell; (ii) Male germ cell; (iii) Ovary<\/strong>
\n Answer.<\/strong>Difference between unisexual and bisexual flowers
\n<\/p>\n
\n(i) that produces eggs.<\/strong>
\n(ii) where fusion of egg and sperm takes place.<\/strong>
\n(iii) where zygote is implanted.<\/strong>
\nWhat happens to human egg when it is not fertilised?<\/strong>
\n Answer.<\/strong>
\n<\/p>\n
\nQuestion.25 The aqueous solutions of copper sulphate and zinc sulphate appear<\/strong>
\n (A) blue and green respectively (B) green and colourless respectively<\/strong>
\n (C) blue and brown respectively (D) blue and colourless respectively<\/strong>
\n Answer.<\/strong>(D) blue and colourless respectively<\/p>\n
\n (A) no reaction<\/strong>
\n (B) a colourless gas with pungent smell<\/strong>
\n (C) bubbles of a colourless and odourless gas<\/strong>
\n (D) a strong smell of vinegar<\/strong>
\n Answer.<\/strong>(C) bubbles of a colourless and odourless gas<\/p>\n
\n (A) It hums blue litmus red and smells like vinegar<\/strong>
\n (B) It hums blue litmus red and smells like burning sulphur<\/strong>
\n (C) It turns red litmus blue and smells like vinegar<\/strong>
\n (D) It turns red litmus blue and has a fruity smell<\/strong>
\n Answer.<\/strong>(A) It hums blue litmus red and smells like vinegar<\/p>\n
\n (A) a distant tree or an electric pole<\/strong>
\n (B) a well-illuminated distant building<\/strong>
\n (C) well-lit grills of the nearest window<\/strong>
\n (D) a burning candle placed at the distant edge of the laboratory table<\/strong>
\n Answer.<\/strong>(A) a distant tree or an electric pole<\/p>\n
\n (A) a convex lens and a screen<\/strong>
\n (B) a convex lens and a lens holder<\/strong>
\n (C) a lens holder, a screen holder and a scale<\/strong>
\n (D) a convex lens, a screen holder for them and a scale.<\/strong>
\n Answer.<\/strong>(D) a convex lens, a screen holder for them and a scale.<\/p>\n
\n a rectangular glass slab.<\/strong>
\n
\nAnswer.\u00a0<\/strong> (C) III<\/p>\n
\n <\/strong>
\n Answer.<\/strong>\u00a0(A) III, II, IV, I<\/p>\n
\n <\/strong>
\n Answer.<\/strong>
\n<\/p>\n
\n (A) yeast cells do not separate after budding<\/strong>
\n (B) daughter cells are unable to survive without parent cells<\/strong>
\n (C) buds reproduce as soons as they are formed<\/strong>
\n (D) daughter cells stick together with the help of mucus<\/strong>
\n Answer.<\/strong>\u00a0(A) yeast cells do not separate after budding<\/p>\n
\n Answer.<\/strong> Cotyledons are special structures in the seeds of the plants. Cotyledons store food for the embryo of the plant.
\nIn gram seeds, there are two cotyledons and in maize (com) seeds, there is only one cotyledon.<\/p>\n
\n Answer.<\/strong> \u2220i =\u2220e in this case, and these are alternate angles. So incident ray is parallel to the emergent ray.<\/p>\n
\n Answer.<\/strong> When hard water is used in these bioilers, then white scum of salts present in the hard water gets deposited inside the boilers making a white layer. These white layers can be removed by washing the boilers with dil. HCl acid.<\/p>\nSET II<\/strong><\/span><\/h3>\n
\nSECTION A<\/strong><\/span>
\n Question.1 Write the name and formula of the first member of the carbon compounds having functional group\u2014COOH.<\/strong>
\n Answer.<\/strong> First member of carboxylic acid group is:
\nHCOOH \u2014 Methanoic acid.<\/p>\n