PYQ Vault

Day 165: CBSE Class 10 Science

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

  1. Question 1

    Electricity. Asked once: 2025 (same type asked 3 times)

    15
    Four identical resistors of 12 Ω12\,\Omega each are connected in series to form a square ABCD as shown in the figure. The resistance of the network between the two points 1 and 2 is :

    Tap an option to check your answer.

  2. Question 2 (case study, 4 parts)

    Heredity. Asked once: 2022 (same type asked 3 times)

    Sex of an individual is determined by different factors in various species. Some animals rely entirely on the environmental cues, while in some other animals the individuals can change their sex during their life time indicating that sex of some species is not genetically determined. However, in human beings, the sex of an individual is largely determined genetically.
    15 (a)
    In what way are the sex chromosomes ‘X’ and ‘Y’ different in size ? Name the mismatched pair of sex chromosome in humans.
    15 (b)
    Write the number of pair/pairs of sex chromosomes present in human beings. In which one of the parent (male / female) perfect pair / pairs of sex chromosomes are present ?
    15 (c)
    Citing two examples, justify the statement “Sex of an individual is not always determined genetically”.
    15 (c) OR
    Draw a flow chart to show that sex is determined genetically in human beings.

  3. Question 3

    How do Organisms Reproduce?. Asked once: 2022 (same type asked 3 times)

    3
    Give reasons : (i) Placenta is extremely essential for foetal development. (ii) Uterine lining becomes thick and spongy after fertilisation.

  4. Question 4

    Light — Reflection and Refraction. Asked once: 2023 (same type asked 3 times)

    31
    The power of a lens is +4D. Find the focal length of this lens. An object is placed at a distance of 50 cm from the optical centre of this lens. State the nature and magnification of the image formed by the lens and also draw a ray diagram to justify your answer.

  5. Question 5

    Light — Reflection and Refraction. Asked once: 2024 (same type asked 3 times)

    36 (b)
    (i) Draw a ray diagram to show the path of the reflected ray in each of the following cases : A ray of light incident on a convex mirror (1) parallel to its principal axis, and (2) is directed towards its principal focus (ii) A 1.5 cm tall candle flame is placed perpendicular to the principal axis of a concave mirror of focal length 12 cm. If the distance of the flame from the pole of the mirror is 18 cm, use mirror formula to determine the position and size of the image formed.