PYQ Vault

Day 43: CBSE Class 10 Science

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

  1. Question 1

    Magnetic Effects of Electric Current. This type asked 4 times: 2023, 2024, 2025, 2026. This one: 2026

    39 (b)
    (i) (I) In the given circuit diagram, a battery BB, a key KK, a resistance RR and a thick copper wire XY are connected in series and a compass is placed near the wire. What is the purpose of this arrangement ? (II) What conclusion do you draw from it ? (ii) Give reasons : (I) There is either a convergence or a divergence of magnetic field lines near the ends of a current-carrying straight solenoid. (II) The current-carrying solenoid, when suspended freely, aligns along a particular direction. (III) The burnt-out fuse should be replaced by another fuse of identical rating.
  2. Question 2

    Magnetic Effects of Electric Current. This type asked 4 times: 2022, 2023, 2024, 2026. This one: 2026

    Two statements are given, one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer from the options given below.
    32
    Assertion (A) : Direction of force exerted on a current-carrying conductor placed in a magnetic field remains same if the directions of both magnetic field and current flowing through the conductor are reversed. Reason (R) : The direction of force exerted on a current-carrying conductor placed in an external magnetic field can be determined by using magnetic compass.

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  3. Question 3

    Metals and Non-metals. This type asked 4 times: 2023, 2024, 2025, 2026. This one: 2026

    19
    Magnesium ribbon burns with a dazzling white flame and changes into a white powder as shown in the diagram given below : The powder is dissolved in water. Identify the chemical formula of the white powder and the correct change observed when the solution is tested with litmus paper.

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  4. Question 4 (case study, 4 parts)

    Metals and Non-metals. This type asked 4 times: 2023, 2024, 2025, 2026. This one: 2026

    Most of metals occur in combined state in form of ores. Carbonate ores are converted into oxides by calcination and sulphide ores by roasting. Oxides are reduced with suitable reducing agent like carbon to get free metal. Highly reactive metals like – Al, Mg are also used as reducing agents to obtain metal from their oxides. Most reactive metals are obtained by electrolytic reduction of their molten ores. Alloying is a very good method of improving the properties of a metal. We can get desired properties by this method. The electrical conductivity and melting point of an alloy is less than that of pure metals.
    28 (a)
    Why carbonate or sulphide ores are converted to oxides before extraction of metal from it ?
    28 (b)
    Write a reaction in which Aluminium is used as a reducing agent to obtain metal from its oxide.
    28 (c) (i)
    How is copper obtained from its ore (Cu2S)(\mathrm{Cu_2S}) ? Give equations of the reactions.
    28 (c) (ii)
    (I) Why highly reactive metals cannot be obtained from their oxides by using carbon as a reducing agent ? (II) Why solder, an alloy of lead and tin, is used for welding electrical wires together ?
  5. Question 5

    Metals and Non-metals. This type asked 4 times: 2023, 2024, 2025, 2026. This one: 2026

    23
    Galvanization is a process of coating iron articles with a thin layer of zinc to prevent iron from rusting. The iron is protected even if the zinc coating is scratched and iron is exposed. Which of the following is/are true about how zinc prevents the rusting of iron ? (P) A galvanised iron article does not undergo oxidation. (Q) The zinc coating prevents contact of iron with air. (R) Zinc provides continuous protection to iron from rusting.

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