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A net charge of 38 mC passes through the cross-sectional area of a wire in 15 sA net...

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akjohnson95 | Student | eNotes Newbie

Posted May 8, 2012 at 10:18 PM via web

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A net charge of 38 mC passes through the cross-sectional area of a wire in 15 s

A net charge of 38 mC passes through the cross-sectional area of a wire in 15 s.
  (a) What is the current in the wire?
1 (b) How many electrons pass the cross-sectional area in 1.0 min?   

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thilina-g | College Teacher | (Level 1) Educator

Posted May 9, 2012 at 7:15 AM (Answer #1)

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a) The current is defined by,

 

current  = charge / time  or I = Q/t

In words it is it is the amount of charger per second.

Therefore,

I = 38 mC / 15 S

I = 2.533 mA.

 

b) The charge per second is 2.533 mC.

There charge for 1 min = 2.533 x 60

                                 = 152 mC per min

 

The charge of an electron  = 1.602 x 10^(-19) C

Therefore number of electrons per min,

                          = 152 mC per min / 1.602 x 10^(-19) C

                          = 9.488 x 10^17

 

The number of electrons per minute is 9.488 x 10^17.

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