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Assertion If the length of the conductor is doubled, the drift velocity will become half of the original value (keeping potential difference unchanged). Reason At constant potential difference, drift velocity is inversely proportional to the length of the conductor.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Correct answer: Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

Solution

For a conductor, drift velocity is proportional to the electric field, and the electric field is V/L when the potential difference is fixed. So if length doubles while voltage stays the same, the field halves and the drift velocity also halves. Thus both statements are true, and the reason correctly explains the assertion.

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