Current Flow and Electric Field – Rankers Physics
Topic: Current Electricity
Subtopic: Relation between Current and Drift Velocity

Current Flow and Electric Field

Assertion (A): Current flows in conductor only when there an electric field is applied to a conductor.
Reason (R): Drift velocity of \(e^-\) decreases in presence of electric field.
 
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution:

Assertion (A) is true: A net flow of charge (current) in a conductor requires an external electric field to give the free electrons a directional drift. Without a field, electron motion is random, leading to zero net current.


Reason (R) is false: In the presence of an electric field, free electrons experience a force and acquire a net drift velocity in the direction opposite to the electric field. Thus, drift velocity increases, it does not decrease.

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