1. The problem statement, all variables and given/known data Estimate the magnetic field required to maintain protons at 7TeV in the LHC at CERN. The LHC has a circumference of 27 km. State any assumptions or approximations you make. 2. Relevant equations lorentz force, assuming magnetic field is always perpendicular to the direction of motion: F=qvB (q=charge of the proton) such that we can use the Formula for centripetal force: F=1/r mv^2 ---equating the two yields the cyclotron formula: B=mv/qr relate momentum to mass velocity: p=mv then B=p/qr is the equation we need ( I think) 3. The attempt at a solution I'm not completely sure as how to use the 7TeV energy given, this probably includes mass so I use the equation: E=p^2+M^2 assuming c=1 and all units are as such. I immediately notice that the mass of the proton is 938 MeV, this is a negligible amount compared to the 7TeV, so I suggest we just ignore the mass of the proton for this problem and treat all energy as kinetic energy such that: B=p/qr=(7* (5.36 x 10^-16 )kg m /s)/[(1.6022*10^-19 C)(27 * 10^3 m)]=0.867Teslas. Am I making any mistakes here or do you guys get similar answers?