Question

A current of $5 \,A$ is passing through a metallic wire of cross-sectional area $ 4\times {{10}^{-6}}{{m}^{2}} $ . If the density of charge carriers of the wire is $ 5\times {{10}^{26}} $ $ {{m}^{-3}}, $ the drift velocity of the electrons will be

• A. $ 1\times {{10}^{2}}m{{s}^{-1}} $
• B. $ 1.56\times {{10}^{-2}}m{{s}^{-1}} $
• C. $ 1.56\times {{10}^{-3}}m{{s}^{-1}} $
• D. $ 1\times {{10}^{-2}}m{{s}^{-1}} $

Answer 1

Answer: (B)

Drift velocity, $ {{v}_{d}}=\frac{I}{neA} $
$ \Rightarrow $ $ {{v}_{d}}=\frac{5}{(5\times {{10}^{26}})\times (1.6\times {{10}^{-19}})\times (4\times {{10}^{-6}})} $
$ =1.56\times {{10}^{-2}}m{{s}^{-1}} $