In: Physics
) A coaxial cable consists of a cylinder of radius ? surrounding by a thin cylindrical shell of radius 2?. Suppose the cable is along the ?-axis. The current density in inner cylinder is ? ⃗= (?0 + ??)?̂, where ?0 > 0 and ? > 0 are constant. The current in the outer shell, ?? ,is downward (−? direction). a) Find the magnetic field in regions 0 < ? < ?,? < ? < 2? and 2? < ?. b) Find the magnetic force on a point charge, +? on ?-axis at distance 3? from the axis of the cable, if it is traveling with velocity of ? ⃗ = ?? ̂ c) Find the magnetic force on a point charge, −? on ?-axis at distance 4? from the axis of the cable, if it is traveling with velocity of ? ⃗ = ??