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NEET2017PhysicsMechanical Properties of FluidsActual

Assertion : A needle placed carefully on the surface of water may float, whereas the ball of the same material will always sink. Reason : The buoyancy of an object depends both on the materials and shape of the object.

Options

  1. AIf both assertion and reason are true and reason is the correct explanation of assertion.
  2. BIf both assertion and reason are true but reason is not the correct explanation of assertion.
  3. CIf assertion is true but reason is false.
  4. DIf both assertion and reason are false.

Correct answer

C. If assertion is true but reason is false.

Step-by-step solution

(c) : When a needle is placed carefully on the surface of water, it floats on the surface of water due to the surface tension of water, which does not allow the needle to sink. In case of a steel ball, the surface tension of the water is not sufficient to keep it floating, so it sinks down.

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