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What happens to the drift velocity (v_(d)) of electrons and to the resistance (R), if the length of a conductor is doubled (keeping potential difference unchanged)? |
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Answer» Solution :Drift velocity of free electron is given by `v_(d)=(EE)/(m)TAU` where `E=("Pot. Diff.")/("LENGTH")=(V)/(l)` So `v_(d)=(eV)/(ml)tau` i.e. `v_(d)prop(1)/(l)`(if `(eVtau)/(m)` is constant). It means if l is doubled keeping pot. diff. unchanged), the drift velocity will become half of the ORIGINAL value. we know, resistance `Rpropl` (length of the conductor) therefore, the resistance of the conductor becomes double of the original value when length of the conductor is doubled. |
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