1. The problem statement, all variables and given/known data A current of 1A is flowing down a long cylindrical conductor of radius 8mm. A long cylindrical hole of radius 2mm runs along the conductor with the axis of the hole offset 3mm from the centre of the conductor. What is the magnetic field i) on the axis of the conductor, and ii) on the axis of the hole? Ans: 3.54A/m, 7.96A/m 2. Relevant equations B field in a cylinder radius a with a hole through the centre = μIr/2pi(a^2) 3. The attempt at a solution I found that if you have a cylinder with a hole bored off-centre so that the axis of the hole is displaced from the axis of the cylinder then the field in the hole is perfectly uniform and the flux lines are parallel straight lines along the length of the cylinder. How do I know what the strength of the magnetic field in the hole is? And then how do I use this to answer the question?