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Science Assertion (A) & Reason (B) MCQ

Air Around Us · CBSE STD 6 (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
DIRECTIONS: Read the passage(s) given below and answer the questions that follow Passage - If in a closed room there is some material that is burning, you may have felt suffocation. This is due to excess carbon dioxide that may be accumulating in the room. Plants and animals consume oxygen for respiration and produce carbon dioxide.
Assertion (A): Aquatic animals use dissolved air (or oxygen) in water for respiration.
Reason (R): When fuel is burnt, a smoke is produced.
  • 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 $A$
Both $A$ and $R$ are true but $R$ is not the correct explanation of $A.$
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MCQ 21 Mark
DIRECTIONS: Read the passage(s) given below and answer the questions that follow Passage - If in a closed room there is some material that is burning, you may have felt suffocation. This is due to excess carbon dioxide that may be accumulating in the room. Plants and animals consume oxygen for respiration and produce carbon dioxide.
Assertion (A): The gases nitrogen and oxygen together make 90% (by volume) of air.
Reason (R): Air contains some dust particles.
  • 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

$A$ is incorrect and $R$ is correct. [percentage of nitrogen + oxygen =$ 99\%].$

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MCQ 31 Mark
DIRECTIONS: The questions in this segment consists of two statements, one labelled as assertion $A?$ And the other labelled as "reason $R??$. You are to examine these two statements carefully and decide if the assertion $A$ and reason $R$ are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below.
Assertion (A): Air is a homogeneous mixture of gases.
Reason (R): The composition of every part of a homogeneous mixture is same.
  • ✓
    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 $A$
Both $A$ and $R$ are true and $R$ is the correct explanation of $A$
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MCQ 41 Mark
DIRECTIONS: Read the passage$(s)$ given below and answer the questions that follow Passage - If in a closed room there is some material that is burning, you may have felt suffocation. This is due to excess carbon dioxide that may be accumulating in the room. Plants and animals consume oxygen for respiration and produce carbon dioxide.
Assertion (A): Atmosphere is essential for life on earth.
Reason (R): Carbon dioxide is a colourless, odourless gas present in air.
  • 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 $A$
Both $A$ and $R$ are true but $R$ is not the correct explanation of $A.$
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