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9.1 , fluid mechanics — Physics STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 SciencePhysics9.1 , fluid mechanics1 Mark
MCQ
$Assertion :$ A thin stainless steel needle can lay floating on a still water surface.
$Reason :$ Any object floats when the buoyancy force balances the weight of the object
  • A
    If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
  • ✓
    If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
  • C
    If the Assertion is correct but Reason is incorrect.
  • D
    If both the Assertion and Reason are incorrect.
✓

Answer

Correct option: B.
If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
b
Assertion and Reason are correct. But Reason does not explain Assertion. Explanation of Assertion is that it is the surface tension of the water surface which is balancing the weight of the steel needle.

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