This is a true or false question relating magnetic field and work: A current-carryign wire placed in a magnetic field will gain kentic energy as the wire accelerates in response to the magnetic force. However, in applying the definition of work, ( W = F * D * cos x ), we realize that the magnetic field cannot do work on a charged particle because the force on the particle is perpendicular to its motion. Froom this we conclude that the magnetic force is an exception to the rule. Personally, i think the statement is false. but I really can't find a way to prove it. Can someone throw in some insight into this?