- #1

PumpkinCougar95

## Homework Statement

This is irodov's problem #310 in electrodynamics

A long solenoid of cross-sectional radius

**a**has a thin insulated wire ring tightly put on its winding; one half of the ring has the resistance ## \beta ## times that of the other half. The magnetic induction produced by the solenoid varies with time as B = bt, where b is a constant. Find the magnitude of the electric field strength in the ring.

## Homework Equations

Provided solution:

https://drive.google.com/file/d/0B2jHGkWhC0E2eWtIOXV2SWFVdmM/view?usp=sharing

## The Attempt at a Solution

Why have we not used the formula :

## E = \frac {r}{2} \frac {dB} {dt} ## for the Electric field , where r is the radius of the circle.

Why is the electric field dependent on the resistance?

Also, How can charges just accumulate in a wire? Why doesn't this happen in other cases?

Lastly, The solution states that the current in the 2 sections must be different, yet it has taken the current to be the same in its first two equations, why is this?

Thanks for your help!