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The number of free electrons per 100 mm ...

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?

A

`5 A`

B

`80 A`

C

`8 A`

D

`0.8 A`

Text Solution

Verified by Experts

The correct Answer is:
D
`I = "ne A" v_(d) = 2 xx 10^(21) xx 1.6 xx 10^(-19) xx 10 xx 0.25xx 10^(-3)`
`= 2 xx 1.6 xx 0.25 = (8)/ (10)= 0.8 A`
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