- #1
wayneinsane
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Homework Statement
There is uniform magnetic field of 25 mT into paper in a region.
Where there is kink in a wire..
The initial diameter of the kink is 2 cm. The wire is pulled out and kink shrinks to dosimeter = 0 in 50 ms.
(i) Determine the average voltage between A and B. and the polarity of A and B.
(ii) Suppose the kink is undisturbed and the magnetic field increases to 100 mT in 4 x 10-3 s, then determine the average voltage between A and B and the polarity of A and B.
Homework Equations
magnetic flux = BAcos(theta)
emf = -N magnetic flux / delta T
The Attempt at a Solution
for (i), I did magnetic flux = BAcos(theta)... B = 2.5x10^-2 T, A = 3.14x10^-4, and cos theta = 1... so mag flux = 7.85x10^-6...so plug that into emf and you get 7.85x10^-6/50x10^-3s and you get 1.57x10^-4V...is this correct??
for (ii) i did change in flux so Bf x A - Bi x A which is 5.14x10^-5 T - 7.85 x 10^-6 T which gives 2.355 x 10^-5T... you plug that into EMF equation and get 2.355x10^-5T/4x10^-3s which equals 5.89x10^-3V...is this correct??