... only part ofthe problem was used at a different school, we have indicated which one.We have also tried to establish a balance between standard problems thatare popular with many physics departments ... between vacuum and a space half-filled with superconductor, with an external field parallel to theboundary, and estimate for a typical metal superconductor atzero temperature, assuming3.67 ... vertical changes and one forsmall radial changes. Neglect any coupling between radial and verticalmotion.For what range of is the orbit stable against both vertical and radialperturbations?d)3.64...