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cjavier
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Homework Statement
A parallel-plate capacitor of capacitance C with circular plates is charged by a constant current I. The radius a of the plates is much larger than the distance d between them, so fringing effects are negligible. Calculate B(r), the magnitude of the magnetic field inside the capacitor as a function of distance from the axis joining the center points of the circular plates.
Homework Equations
When a capacitor is charged, the electric field E, and hence the electric flux Φ, between the plates changes. This change in flux induces a magnetic field, according to Ampère's law as extended by Maxwell:
∮B⃗ ⋅dl⃗ =μ0(I+ϵ0dΦdt).
You will calculate this magnetic field in the space between capacitor plates, where the electric flux changes but the conduction current I is zero.
The Attempt at a Solution
Since the I on the left is zero, I just say the answer is μϵ0dΦdt. This becomes μI which is incorrect.