The radiation detector known as a Geiger counter uses aclosed,
hollow, cylindrical tube with an insulated wire along itsaxis.
Suppose a Geiger tube, as it's called, has a1.0-{\rm
mm}-diameter wire in a tubewith a 25 {\rm mm} inner diameter.
The tube isfilled with a low-pressure gas whose dielectric
strength is1.0\times 10^6 {\rm{ V/m}}.  What is the maximum
potential difference between the wire and thetube?  \Delta
V_{\rm max} =___________kV