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**The Force on an Electron...??**

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.

**F**e = q

**E**.

By deriving

**B**in the problem, is it correct to say that I got the

**E**field? (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 the

**E**field, 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!**