Current Electricity 1 Question 17
17. A steady current flows in a metallic conductor of non-uniform cross-section. The quantity/quantities constant along the length of the conductor is/are
(1997, 1M)
(a) current, electric field and drift speed
(b) drift speed only
(c) current and drift speed
(d) current only
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Solution:
$$ \text { Drift speed, } \quad v _d=\frac{1}{n e A} \propto \frac{1}{A} $$
Therefore, for non-uniform cross-section (different values of $A$ ) drift speed will be different at different sections. Only current (or rate of flow of charge) will be same.
