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downwithsocks
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Homework Statement
A wire carries a current and consists of three sections with different radii. Rank the sections according to the following quantities, greatest first: (a) current, (b) magnitude of current density, and (c) magnitude of electric field.
Homework Equations
i = int(J).dA
The Attempt at a Solution
a) A = B = C since charge is conserved and the same amount of current must enter and leave each section. Is this correct?
b) From the given equation, J = i/A. So the cross section with the greatest area will have the lowest current density, thus B > C > A. Correct?
c) Intuition tells me A > C > B but I can't even really convince myself that that's correct let alone explain why with an equation, could anybody help me along?