PYQ Vault

Day 154: CBSE Class 10 Science

5 questions (8 parts). Try each one first, then open its answer.

  1. Question 1

    Heredity. Asked once: 2024 (same type asked 4 times)

    30
    List two differences between dominant traits and recessive traits. What percentage of pea plants in the F2\mathrm{F_2} generation were with yellow seeds in Mendel’s cross between the pea plants having yellow (YY) and green coloured (yy) seeds ?

  2. Question 2 (case study, 4 parts)

    How do Organisms Reproduce?. Asked once: 2023 (same type asked 4 times)

    All the reproductive methods of living organisms are broadly categorized into two types : 1. Asexual reproduction, and 2. Sexual reproduction. Asexual reproduction involves the participation of a single parent without the formation of gametes, fertilisation and transfer of genetic material. This method is a common means of rapidly increasing offsprings under favourable conditions.
    38 (a)
    Name the type of fission that occurs in Leishmania and Plasmodium.
    38 (b)
    Write one advantage of sexual mode of reproduction over asexual reproduction.
    38 (c)
    Give reasons why : (i) Colonies of yeast fail to multiply in water but multiply in sugar solution. (ii) Rhizopus individuals do not grow on a dry slice of bread.
    38 (c) OR
    Name the filamentous structures a student could identify when he collected water from a pond that appeared dark green. How do these organisms multiply ? Explain.

  3. Question 3

    Metals and Non-metals. Asked once: 2022 (same type asked 4 times)

    2
    The atomic number of an element ‘X’ is 11. (i) Write the electronic configurations of X and find its valency. (ii) Write the formula and nature of its oxide.

  4. Question 4

    Acids, Bases and Salts. Asked once: 2023 (same type asked 3 times)

    21 (a)
    On heating ‘X’ at 373 K, it loses water molecules and becomes ‘Y’. ‘Y’ is a substance which doctors use for supporting fractured bones in the right position. (i) Identify ‘X’ and ‘Y’. (ii) How can ‘X’ be reobtained from ‘Y’ ?

  5. Question 5

    Acids, Bases and Salts. Asked once: 2024 (same type asked 3 times)

    2
    An aqueous solution of a salt turns blue litmus to red. The salt could be the one obtained by the reaction of :

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