Question

A potential difference $V$ is applied to a copper wire of length $l$ and thickness $d$. If $V$ is doubled, the drift velocity:

• A. Is doubled
• B. Is halved
• C. Remain same
• D. Becomes zero

Answer 1

Answer: (A)

Is doubled

In the first case, $E=V/l$ so $E$ is directly proportional to $V$ so $E$ will be doubled. Since $V=IR$ so, $E=IR/l$ so Resistance is doubled and $Vd$ is directly proportional to $E$ so $Vd$ is doubled. So in the case, everything is doubled.