5. Consider a long linear electric charge with a charge density X. (a) What is the magnetic field seen by an observer moving at rest with respect to the wire? (b) What is the current seen by an observer moving at a speed v parallel to the wire? (c) What is the magnetic field measured by the moving observer? (d) Would you expect the measured electric field to also depend on the velocity? Answer quali- tatively there is no need to do a detailed calculation. [Hint: what else changes when you boost into a moving frame? Does this have an effect on the set- up here?]

5. Consider a long linear electric charge with a charge density X. (a) What is the magnetic field seen by an observer moving at rest with respect to the wire? (b) What is the current seen by an observer moving at a speed v parallel to the wire? (c) What is the magnetic field measured by the moving observer? (d) Would you expect the measured electric field to also depend on the velocity? Answer quali- tatively there is no need to do a detailed calculation. [Hint: what else changes when you boost into a moving frame? Does this have an effect on the set- up here?]