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Physics · 2023 · 2 marks
CBSE 2023 · Region 5 · Set 2 · Q24
A potential difference ( V ) is applied across a conductor of length ' L ' and cross-sectional area 'A'. How will the drift velocity of electrons and…
A potential difference ( V ) is applied across a conductor of length ' L ' and cross-sectional area 'A'. How will the drift velocity of electrons and the current density be affected if another identical conductor of the same material were connected in series with the first conductor? Justify your answers.
Marking-scheme solution
Drift velocity of electrons is halved\[v_d = \frac{V}{neAR} \]When another identical conductor of same material were connected in series with the given conductor then total resistance becomes double. Therefore\[v_d' = \frac{v_d}{2} \]Current density is halved\[J = \frac{I}{A} = \frac{V}{RA} \]\[J' = \frac{J}{2} \]
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