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Science Assertion (A) & Reason (B) MCQ

Model Paper 9 · CBSE STD 9 (CBSE - 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): An atom contains a positively charged center called the nucleus of the atom.
Reason (R): The nucleus of an atom is 10,000 times bigger than the atom.
  • 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
  • ✓
    A is true but R is false
  • D
    A is false but R is true.
Answer
Correct option: C.
A is true but R is false
(c) A is true but R is false.
Explanation: An atom contains a positively charged center called the nucleus of the atom. Almost all the mass of the atom is concentrated in the nucleus. The size of the nucleus is many times smaller than the size of the atom. The nucleus of an atom is 10,000 times smaller than the atom.
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MCQ 21 Mark
Assertion (A): Cells of cork or bark are dead, acts as a protective covering.
Reason (R): In leguminous plants, the root nodules harbor nitrogen-fixing bacteria which convert atmospheric nitrogen into nitrates.
  • 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: Cells of cork or bark are dead, compactly arranged without intercellular spaces, and have a chemical called subering in their walls that makes them impervious to gases and water. In this way, it acts as a protective tissue.
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MCQ 31 Mark
Assertion (A): Gaseous state of ammonia is not regarded as vapours.
Reason (R): As the volume of a substance increases, its density increases.
  • 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: A substance which is liquid at room temperature, then its gaseous state is regarded as vapour. Ammonia is gas at room temperature, hence its gaseous state is not regarded as vapour.
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MCQ 41 Mark
Assertion $(A):$ A tiger can accelerate from rest at the rate of $4\ m/s^2$
Reason $(R):$ The velocity attained by it in $10s$ is $40\ m/s.$
  • ✓
    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 $A$
Initial velocity $(u) =0$,
acceleration $(a) =4\ m / s ^2$
$V=u+at$
$V=0+4 \times 10$
$V=40\ m / s$
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Assertion (A) & Reason (B) MCQ - Science STD 9 Questions - Vidyadip