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InterviewSolution
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A potential difference of 100 V is applied to the ends of a copper wire one metre long . What is the average drift velocity of electrons ? (Given, `sigma=5.81xx10^(7)Omega` or `n_(Cu)=8.5xx10^(28)m^(-3)`)A. `0.43 ms^(-1)`B. `0.83 ms^(-1)`C. `0.52 ms^(-1)`D. `0.95 ms^(-1)` |
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Answer» Correct Answer - A Since, `Delta V =100 V, l = 1m` `therefore` Electric field `=(Delta V)/(l)=(100)/(1)=100 Vm^(-1)` Also, conductivity `sigma = 5.81xx10^(7)Sigma^(-1)m^(-1)` `n=8.5xx10^(28)m^(-3)` The average drift velocity of the electrons `v_(d)=(l)/("neA")` `because " " J = sigma E, J=(l)/(A) " (given)"` `therefore " " v_(d)=(sigma)/("en")E` `= (5.81xx10^(7)xx100)/(1.6xx10^(-19)xx8.5xx10^(28))` `=0.43 ms^(-1)` |
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