there is hollow cylinder of radii R carrying current I from one end of cylinder to another point.I mean it is not in circular path it is in straight line. (1) Is there any magnetic field at the cylinder? (2) What is magnetic field at any point inside cylinder. (3) does it feel any pressure due to magnetic field whose origin is it's own current. My answers (1) Yes that is (μI)/(2πR) Here i am confused as it is border line of two regions one is filled with magnetic field and other is without magnetic field. (2)That should zero. Using ampere circuital loop. I ask this because it is interconnected to first question (3) I think no.(not sure). Magnetic field at this point should in circular loop. Making an angle of of 0 radian so magnetic force becomes zero. => pressure=0. Please tell me where am i correct and where am i wrong. thanks for reading.