The number of free electrons per 100 mm of ordinary copper wire is `2xx10^(21)`. The average drift speed of electorn is `0.25 mm//s`. What is the current flowing?

The number of free electrons per 100 mm of ordinary copper wire is `2x

1.	The number of free electrons per 100 mm of ordinary copper wire is `2xx10^(21)`. The average drift speed of electorn is `0.25 mm//s`. What is the current flowing?
Answer» Let A be the area of cross-section of wire. Therefore, number of electrons per unit volume of copper wire is, `n=2xx10^(21)/(A xx (100xx10^(-3)))` Now, `I=n A e v_(d)` `=(2xx 10^(21))/(A xx (100xx10^(-3))) xxA xx (1.6 xx10^(-19))` `xx (0.25 xx 10^(-3))` `= 0.8A`

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The number of free electrons per 100 mm of ordinary copper wire is `2xx10^(21)`. The average drift speed of electorn is `0.25 mm//s`. What is the current flowing?

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