# Dielectric breakdown

by bodensee9
Tags: breakdown, dielectric
 P: 178 1. The problem statement, all variables and given/known data Hello: I am asked to find the maximum voltage in a cylindrical capacitor. The capacitor consists of an inner wire and an outer cylindrical shell. The wire has radius $$r_{1}$$ and the cylinder has inner radius $$r_{2}.$$ The space between the wires is filled with a dielectric having dielectric constant $$\kappa.$$ 2. Relevant equations This is in CGS units (actual calculations have been converted to SI) So I know that the electric field E in a dielectric is $$E_{no_dielectric}/\kappa$$. So then if my cylindrical capacitor has E field = $$\frac{2\lambda}{r}$$, then my E field inside the dielectric material would be $$\frac{2\lambda}{r\kappa}$$. So then if I am given a value for the dielectric strength of the dielectric (say $$A$$, which would happen at the inner radius of the cylindrical shell which is $$r_{2}$$), would I do $$A = \frac{2\lambda}{r\kappa}$$, and then I can find the charge density which is $$\frac{Ar\kappa}{2}$$. And, since the potential between the wire and the shell would be $$2\lambda*ln\frac{r_{2}}{r_{1}}$$, would I just substitute the new value for lambda I got to get the potential? For some reason this was marked wrong? Thanks!

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