PYQ Vault

Day 189: CBSE Class 10 Science

5 questions. Try each one first, then open its answer.

  1. Question 1

    Carbon and its Compounds. Asked once: 2023 (same type asked 2 times)

    34 (a)
    A neutral organic compound ‘X’ (Molecular formula C2H6O\mathrm{C_2H_6O}) on reacting with acidified K2Cr2O7\mathrm{K_2Cr_2O_7} gives an organic compound ‘Y’ which is acidic in nature. ‘X’ reacts with ‘Y’ on warming in the presence of conc. H2SO4\mathrm{H_2SO_4} to give a sweet smelling compound ‘Z’. (i) Identify ‘X’, ‘Y’ and ‘Z’. (ii) Write the chemical equations for the reactions in the conversion of (1) ‘X’ to ‘Y’ and (2) ‘X’ to ‘Z’. (iii) State the role of (1) acidified K2Cr2O7\mathrm{K_2Cr_2O_7} in the conversion of ‘X’ to ‘Y’ and (2) conc. H2SO4\mathrm{H_2SO_4} in the reaction of ‘X’ and ‘Y’. (iv) Name the reaction which occurs when ‘Z’ reacts with an alkali.

  2. Question 2

    How do Organisms Reproduce?. Asked once: 2024 (same type asked 2 times)

    10
    A zygote is formed by the fusion of a male gamete and a female gamete. The number of chromosomes in the zygote of a human is :

    Tap an option to check your answer.

  3. Question 3

    Light — Reflection and Refraction. Asked once: 2023 (same type asked 2 times)

    36
    (a) Name the type of mirror that should be used to obtain the following types of images : (i) A magnified and virtual image of an object (ii) A diminished and virtual image of an object (b) Draw labelled ray diagrams to justify your answers in each case mentioned above. (c) Which of these mirrors can also be used to obtain a magnified and real image of an object ? State the position of the object in this case.

  4. Question 4

    Electricity. Asked once: 2023 (same type asked 5 times)

    36
    (a) An electric iron consumes energy at a rate of 880 W when heating is at the maximum rate and 330 W when the heating is at the minimum. If the source voltage is 220 V, calculate the current and resistance in each case. (b) What is heating effect of electric current ? (c) Find an expression for the amount of heat produced when a current passes through a resistor for some time.

  5. Question 5

    Magnetic Effects of Electric Current. Asked once: 2024 (same type asked 5 times)

    32
    (a) What happens when a bundle of wires of soft iron is placed inside the coil of a solenoid carrying a steady current ? Name the device obtained. Why is it called so ? (b) Draw the magnetic field lines inside a current carrying solenoid. What does this pattern of magnetic field lines indicate ?