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A beam contains 2 xx 10^(8) doubly charg...

A beam contains `2 xx 10^(8)` doubly charged positive ions per cubic centimeter, all of which are moving with a speed of `10^(5) m//s` . The current density is

A

`6.4 A//m^(2)`

B

`3.2 A//m^(2)`

C

`1.6 A//m^(2)`

D

None of these

Text Solution

Verified by Experts

The correct Answer is:
A
`I = n(ze)Av_(d)`
`rArr I/A =J (ze)v_(d)`
`J = 2 xx 10^(8) xx 2 xx 1.6 xx 10^(-19) xx 10^(5)`
`= 6.4 xx 10^(-6) A//m^(2)`
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