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If the length of a wire conductor is dou...

If the length of a wire conductor is doubled by stretching it, keeping the P.D. across it constant, by what factor does the drift speed of electrons change?

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In this case `v_d=1/l`. The drift speed is reduces by half. Drift speed is given by `V_d=e/mtauE=(e tau)/m V/l` (with usual notatins).
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