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NEET2014PhysicsCurrent ElectricityActual

Assertion: Current is passed through a metallic wire so that it becomes red hot. When cold water is poured on half of its portion, the rest of the half portion becomes more hot. Reason: Resistance decreases due to decrease in temperature.

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

A. If both assertion and reason are true and reason is the correct explanation of assertion.

Step-by-step solution

The resistance of that half portion of the metallic wire (heated red hot) on which cold water is poured decreases due to fall in its temperature. This results in a decrease in the resistance of the entire wire. As a result, the current in the wire increases and the other half portion becomes hotter than before.

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