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Author Topic: Physics help :(  (Read 989 times)

Offline Superstrings

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Physics help :(
« on: November 11, 2009, 09:48:13 am »
question is from may june 05, multi-choice, #32

A copper wire of cross sectional area of 2mm^2 carries a current of 10A.
How many electrons pass through a given cross-section of the wire in one second?

A. 1.0 x 10^1
B. 5. x 10^6
C. 6.3 x 10^19
D. 3.1 x 10^25

I have no idea how to do this :(
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Offline Superstrings

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Re: Physics help :(
« Reply #1 on: November 11, 2009, 10:03:59 am »
Nvm resolved >_>

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Offline astarmathsandphysics

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Re: Physics help :(
« Reply #2 on: November 11, 2009, 11:29:31 am »
One mo
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Offline astarmathsandphysics

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Re: Physics help :(
« Reply #3 on: November 11, 2009, 11:35:57 am »
Q=It
ne=I81
n=I/e=10/1.6*10^-19=6.3*10^19
I think thay want you to change it to unit csa ie scale up from 2mm^2 to 1m^2 which is a sclae factor of 50000 ans =e
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