{"id":33905,"date":"2019-10-25T13:16:18","date_gmt":"2019-10-25T07:46:18","guid":{"rendered":"https:\/\/www.cbselabs.com\/?p=33905"},"modified":"2021-09-18T15:15:58","modified_gmt":"2021-09-18T09:45:58","slug":"cbse-previous-year-question-papers-class-10-science-sa2-delhi-2015","status":"publish","type":"post","link":"https:\/\/www.cbselabs.com\/cbse-previous-year-question-papers-class-10-science-sa2-delhi-2015\/","title":{"rendered":"CBSE Previous Year Question Papers Class 10 Science SA2 Delhi 2015"},"content":{"rendered":"

CBSE Previous Year Question Papers Class 10 Science SA2 Delhi 2015<\/strong><\/span><\/h2>\n

Time 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 \u00a0Maximum marks: 90<\/strong>
\nGeneral Instructions:<\/span><\/strong><\/p>\n

    \n
  1. The Question Paper comprises two Sections, A and B. You are to attempt both the Sections.<\/strong><\/li>\n
  2. All questions are compulsory.<\/strong><\/li>\n
  3. There is no choice in any of the questions.<\/strong><\/li>\n
  4. All questions of Section-A and all questions of Section B are to be attempted separately.<\/strong><\/li>\n
  5. Question numbers 1 to 3 in Section A are one mark questions. These are to be answered in one word or in one sentence.<\/strong><\/li>\n
  6. Question numbers 4 to 6 in Section A are two marks questions. These are to be answered in about 30 words each.<\/strong><\/li>\n
  7. Question numbers 7 to 18 in Section A are three marks questions. These are to be answered in about 56 words each.<\/strong><\/li>\n
  8. Question numbers 19 to 24 in Section A are five marks questions, these are to be answered in about 70 words each.<\/strong><\/li>\n
  9. \u00a0Question numbers 25 to 33 in Section B are multiple choice questions based on practical skills. Each question is a one mark question. You are to select one most appropriate response out of the four provided to you.<\/strong><\/li>\n
  10. Question numbers 34 to 36 in Section B are two marks questions based on practical skills. These are to be answered in brief.<\/strong><\/li>\n<\/ol>\n

    SET I<\/strong><\/span><\/h3>\n

    SECTION A<\/strong><\/span>
    \nQuestion.1. Write the name and formula of the 2nd member of homologous series having general formula\u00a0Cn<\/sub>H2n<\/sub>.<\/strong>
    \nAnswer.<\/strong> Cn<\/sub>H2n<\/sub> = Alkene
    \n2nd member = C3<\/sub>H6<\/sub> (Propene)<\/p>\n

    Question.2. List two functions performed by the testis in human beings.<\/strong>
    \nAnswer.<\/strong> Two functions of testes are:<\/p>\n

      \n
    1. To produce the male sex cells (gametes) called sperms.<\/li>\n
    2. To secrete the male sex hormone called testosterone which is responsible for secondary sexual changes in males.<\/li>\n<\/ol>\n

      Question.3. What is the function of ozone in the upper atmosphere? <\/strong>
      \nAnswer.<\/strong> Ozone layer is very important for the existence of life on earth. The function of the ozone layer in the upper atmosphere is to absorb most of the harmful ultraviolet radiations coming from the sun and prevent them from reaching the earth’s surface.<\/p>\n

      Question.4. List four characteristics of the images formed by plane mirrors. <\/strong>
      \nAnswer.<\/strong> The characteristics of the images formed by plane mirrors are:<\/p>\n

        \n
      1. The image formed by a plane mirror is virtual and erect. It cannot be received on a screen.<\/li>\n
      2. The image formed by a plane mirror is of the same size as the object.<\/li>\n
      3. The image formed by a plane mirror is at the same distance behind the mirror as the object is in front of the mirror.<\/li>\n
      4. \u00a0The image formed in a plane mirror is laterally inverted.<\/li>\n<\/ol>\n

        Question.5. Why are forests considered “biodiversity hot spots”? List two ways in which an individual can contribute effectively to the management of forests and wildlife. <\/strong>
        \nAnswer.<\/strong> Due to the presence of a large number of species (of plants and animals) threatened with extinction, forests are said to be ‘biodiversity hotspots’.
        \nThe two ways in which an individual can contribute effectively to the management of forests and wildlife are:<\/p>\n

          \n
        1. As individuals we can try to cut down the use of products directly obtained from forests such as gum, rubber, wood, paper, etc., thereby protecting against the excessive cutting of trees.<\/li>\n
        2. \u00a0As individuals we must discourage and protect against the poaching of wild animals for commercial use.<\/li>\n<\/ol>\n

          Question.6. What is meant by “sustainable management”? Why is reuse considered better than recycling? <\/strong>
          \nAnswer.<\/strong> The development and management of resources in such a way which meets the current basic human needs and also preserves the resources for the needs of future generations, is called sustainable management.
          \nThe process of ‘reuse’ is considered better than the process of ‘recycling’ because recycling requires the use of a large amount of energy and money whereas no energy is required for reusing materials.<\/p>\n

          Question.7. With the help of an example, explain the process of hydrogenation. Mention the essential conditions for the reaction and state the change in physical property with the formation of the product.<\/strong>
          \nAnswer.<\/strong> Process of hydrogenation:
          \n\"cbse-previous-year-question-papers-class-10-science-sa2-delhi-2015-1\"
          \nThe addition of hydrogen to an unsaturated hydrocarbon to obtain a saturated hydrocarbon is called hydrogenation.
          \nEssential conditions for the reaction are:<\/strong><\/p>\n

            \n
          1. Presence of an unsaturated hydrocarbon.<\/li>\n
          2. Presence of a catalyst such as nickel<\/li>\n
          3. or palladium.<\/li>\n<\/ol>\n

            Changes observed:<\/strong><\/p>\n