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Free practice for Class 10 board exams: Bihar Board (BSEB) and CBSE, in Hindi and English.

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Ten new questions every day. The same set for everyone.

  1. Heating lead nitrate gives off brown fumes. Which gas are these brown fumes?

    1. (A) Oxygen (O₂)
    2. (B) Nitrogen (N₂)
    3. (C) Lead oxide (PbO)
    4. (D) Nitrogen dioxide (NO₂)
    Show answer

    Correct answer: (D) Nitrogen dioxide (NO₂)

    Explanation: 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂. The nitrogen dioxide given off is a brown gas.

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  2. What colour does an acid turn blue litmus paper?

    1. (A) Green
    2. (B) Yellow
    3. (C) Red
    4. (D) No change
    Show answer

    Correct answer: (C) Red

    Explanation: Acids turn blue litmus red, while bases turn red litmus blue.

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  3. For which value of k does the pair x + 2y = 3 and 5x + ky + 7 = 0 have no solution?

    1. (A) 10
    2. (B) 5
    3. (C) 2
    4. (D) −10
    Show answer

    Correct answer: (A) 10

    Explanation: For x + 2y − 3 = 0 and 5x + ky + 7 = 0, a₁/a₂ = 1/5, b₁/b₂ = 2/k and c₁/c₂ = −3/7. For no solution, 1/5 = 2/k, so k = 10; and 1/5 ≠ −3/7 holds.

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  4. After how many decimal places does the decimal expansion of 17/8 terminate?

    1. (A) 1
    2. (B) 2
    3. (C) 3
    4. (D) 4
    Show answer

    Correct answer: (C) 3

    Explanation: 17/8 = 17 × 125 / (8 × 125) = 2125/1000 = 2.125. The denominator is 2³, so the expansion ends after 3 decimal places.

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  5. What is the product of the three zeroes of 2x³ − 5x² − 14x + 8?

    1. (A) 4
    2. (B) 5/2
    3. (C) −4
    4. (D) −7
    Show answer

    Correct answer: (C) −4

    Explanation: Product of the three zeroes = −d/a = −8/2 = −4. (The zeroes are 4, −2 and 1/2: 4 × (−2) × 1/2 = −4.)

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  6. Which quadratic equation has the roots 2 and −3?

    1. (A) x² + x − 6 = 0
    2. (B) x² − x − 6 = 0
    3. (C) x² + x + 6 = 0
    4. (D) x² − 5x + 6 = 0
    Show answer

    Correct answer: (A) x² + x − 6 = 0

    Explanation: (x − 2)(x + 3) = x² + x − 6. So the equation is x² + x − 6 = 0.

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  7. What is called the "energy currency" of the cell?

    1. (A) Glucose
    2. (B) ATP
    3. (C) Pyruvate
    4. (D) Haemoglobin
    Show answer

    Correct answer: (B) ATP

    Explanation: The energy released in respiration is stored as ATP molecules. Whenever a cell needs energy, it gets it by breaking down ATP.

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  8. What is the sum of the zeroes of 6x² − 7x − 3?

    1. (A) −7/6
    2. (B) −1/2
    3. (C) 1/2
    4. (D) 7/6
    Show answer

    Correct answer: (D) 7/6

    Explanation: For ax² + bx + c, the sum of the zeroes is −b/a. Here a = 6 and b = −7, so the sum is 7/6. (The zeroes are 3/2 and −1/3.)

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  9. What kind of reaction is respiration?

    1. (A) Exothermic
    2. (B) Endothermic
    3. (C) Displacement
    4. (D) Double displacement
    Show answer

    Correct answer: (A) Exothermic

    Explanation: In respiration, glucose combines with oxygen to form CO₂ and water, releasing energy. A reaction that releases energy is exothermic.

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  10. How many solutions does the pair 2x − 3y = 8 and 4x − 6y = 9 have?

    1. (A) Exactly one solution
    2. (B) Infinitely many solutions
    3. (C) No solution
    4. (D) Exactly two solutions
    Show answer

    Correct answer: (C) No solution

    Explanation: a₁/a₂ = 2/4 = 1/2 and b₁/b₂ = −3/−6 = 1/2, but c₁/c₂ = 8/9. Since a₁/a₂ = b₁/b₂ ≠ c₁/c₂, the lines are parallel and there is no solution.

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