| ASSERTION: The current flowing through a conductor is directly proportional to the drift velocity. |
| REASON: As the drift velocity increases the current following through the conductor decreases. |
A) If both assertion and reason are true and reason is the correct explanation of assertion.
B) If both assertion and reason are true and reason is not the correct explanation of assertion.
C) If assertion is true but reason is false.
D) If both assertion and reason are false.
E) If assertion is false but reason is true.
Correct Answer: C
Solution :
Consider a conductor of length l and area of cross section A. Time taken by the free electrons to cross the conductor, \[t=\frac{l}{{{v}_{d}}}\] Hence current \[l=\frac{q}{t}=\frac{Al\times ne}{l/{{v}_{d}}}\] Or \[I=Ane{{v}_{d}}\] Or \[I\propto \,{{v}_{d}}\] Thus current is directly proportional to drift velocity.
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