If the potential difference applied across a metallic wire of length is doubled while keeping its temperature constant, what happens to the drift velocity of free electrons in the wire?
Answer and explanation
Correct answer: C. It is doubled
- Step 1: Drift velocity is given by .
- Step 2: Because is directly proportional to the applied voltage , doubling the potential difference doubles the drift velocity.
Answer
It is doubled.
Why not the others: Remaining unchanged ignores electric field dependence; being halved confuses inverse with direct proportionality; and fourfold increase incorrectly squares the voltage factor.
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