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Science Assertion (A) & Reason (B) MCQ

Model Paper 8 · Gujarat Board (GSEB) STD 9 (GSEB - English Medium). 4 questions.

Questions

Assertion (A) & Reason (B) MCQ

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4 questions · auto-graded multiple-choice test.

MCQ 11 Mark
Assertion (A): Rutherford's atomic model was that it could not explain the stability of atoms.
Reason (R): Any charged particle during acceleration would radiate energy, and while revolving, it would lose its energy and eventually fall into the nucleus.
  • ✓
    Both A and R are true and R is the correct explanation of A
  • B
    Both A and R are true but R is not the correct explanation of A
  • C
    A is true but R is false.
  • D
    A is false but R is true.
Answer
Correct option: A.
Both A and R are true and R is the correct explanation of A
(a) Both A and R are true and R is the correct explanation of A.
Explanation: Rutherford’s atomic model could not explain how moving electrons could remain in their orbits. Any charged
particle during acceleration would radiate energy, and while revolving, it would lose its energy and eventually fall into the
nucleus. This means that the atom would be highly unstable. But, the matter is composed of stable atoms. Thus, the major
drawback of Rutherford’s atomic model was that it could not explain the stability of atoms.
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MCQ 21 Mark
Assertion (A): Blood is a fluid connective tissue.
Reason (R): It is composed of plasma, platelets, red blood cells, and white blood cells.
  • A
    Both A and R are true and R is the correct explanation of A
  • ✓
    Both A and R are true but R is not the correct explanation of A
  • C
    A is true but R is false.
  • D
    A is false but R is true.
Answer
Correct option: B.
Both A and R are true but R is not the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A.
Explanation: Blood is a fluid connective tissue. It consists of two components - fluid and corpuscles. It is composed of plasma, platelets, red blood cells, and white blood cells.

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MCQ 31 Mark
Assertion (A): The conversion of gas directly into solid is called condensation.
Reason (R): Naphthalene leaves residue when kept open for some time.
  • A
    Both A and R are true and R is the correct explanation of A.
  • B
    Both A and R are true but R is not the correct explanation of A
  • C
    A is true but R is false.
  • ✓
    A is false but R is true.
Answer
Correct option: D.
A is false but R is true.
(d) A is false but R is true.
Explanation: The conversion of gas directly into a solid is called desublimation. Naphthalene does not leave any residue when
kept open for some time.
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MCQ 41 Mark
Assertion (A): A bus moving due north takes a turn and starts moving towards the east with the same speed.There will be no change in the velocity of the bus.
Reason (R): Velocity is a vector quantity.
  • A
    Both A and R are true and R is the correct explanation of A
  • B
    Both A and R are true but R is not the correct explanation of A
  • C
    A is true but R is false.
  • ✓
    A is false but R is true
Answer
Correct option: D.
A is false but R is true
(d) A is false but R is true.
Explanation: As velocity is a vector quantity, its value changes with change in direction. Therefore when a bus takes a turn from north to east its velocity will also change.

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