Current Electricity Charging Discharging Of Capacitors Question 350
Question: There is a current of 20 amperes in a copper wire of $ {{10}^{-6}} $ square metre area of cross-section. If the number of free electrons per cubic metre is $ 10^{29} $ , then the drift velocity is
Options:
A) $ 125\times {{10}^{-3}}m/sec $
B) $ 12.5\times {{10}^{-3}}m/sec $
C) $ 1.25\times {{10}^{-3}}m/sec $
D) $ 1.25\times {{10}^{-4}}m/sec $
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Answer:
Correct Answer: C
Solution:
$ v _{d}=\frac{i}{nAe}=\frac{20}{10^{29}\times {{10}^{-6}}\times 1.6\times {{10}^{-19}}} $
$ =1.25\times {{10}^{-3}}m/s $
BETA
