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bsugeology
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Homework Statement
The magnetic field shown in Figure P20.61 has a uniform magnitude of 29.00 mT directed into the paper. The initial diameter of the kink is 0.30 cm.
(a) The wire is quickly pulled taut, and the kink shrinks to a diameter of zero in 55.00 ms. Determine the average voltage induced between endpoints A and B. (Include the polarity, with + for positive A)
(b) Suppose the kink is undisturbed, but the magnetic field increases to 96.00 mT in 3.65×10-3 s. Determine the average voltage across terminals A and B, including polarity, during this period.
(a) B=.029 T d/2=r=.0015 m A=7.065E-6 m^2 Flux final = 0 t=.055
(b) B=.096 T A=7.065E-6 m^2 Δt=3.65E-3 s
Homework Equations
I think I'm supposed to use the following:
A=∏r^2 Flux=BAcos∅ Emf=-N ΔFlux / Δtime Emf=Flux(final)-Flux(initial) / Δt
The Attempt at a Solution
a) Flux =7.065E-6 X .029 = 2.04E-7 --> Emf= 2.03E-7 / .055 = 3.73E-6 Volts
b)Flux2 =.096 X 7.065E-6 = 6.78E-7 6.78E-7 - 2.04E-7 = 4.74E-7
Emf = 4.74E-7/3.65E-3 s = 1.30E-4 Volts