question_answer

There is a current of 40 ampere in a wire of \[{{10}^{-6}}\,{{m}^{2}}\] area of cross-section.  If the number of free electron per \[{{m}^{3}}\] is \[{{10}^{29}}\],  then the drift velocity will be            [Pb. PMT 2001]

A)            \[1.25\text{ }\times ~{{10}^{3}}m/s\]

B)                                      \[2.50\text{  }\times ~{{10}^{-3}}m/s\]

C)            \[25.0\text{  }\times ~{{10}^{-3}}m/s\]

D)                                      \[250\text{  }\times ~{{10}^{-3}}m/s\]