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Again, hi! I am very thankful for the help that I am being provided. I am yet again stuck in a problem.

I really do not understand it.

For the situation described in Figure P31.32, the magnetic field changes with time according to the expression B = (5.00t3 - 1.00t2 + 0.800) T, and r2 = 2R = 5.00 cm.

(I have also attached the image).

Right now, I have not really tried to solve it, because I want to understand the concept first, but I really don't get it...mostly because I am not sure what equations would be appropriate.

(1)I have thought the equation for electric force would be useful, since they do involve an electron in the problem, and it's what we want to find.Fe = qE.

By derivingBin the problem, is it correct to say that I got theEfield? (Which would therefore allow me to get the Force)

(2)Then I saw in the section where this problem appeared, that they use another type of equation for theEfield, which is:

E= -r/2 * dB/dt

I don't believe that using just these equations in(1)and(2)will give me the right answer though, but after that I don't know what else I am supposed to assume or do.

(3) Also, since the r2 is outside of the circle in the image, I am assuming this is important. But I don't know how to include this in the problem.

I guess that mostly it's the concept that I don't understand. I really appreciate any help that I may get.Thankyou!!

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# Homework Help: The Force on an Electron ?

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