a) A current‐carrying wire bent into a semicircle of radius r forms a close circuit as shown in the figure. A uniform magnetic field is directed normal to the linear section and in the plane of the loop. Show that the magnetic force acting on the closed wire loop is zero. http://upload.wikimedia.org/wikipedia/commons/e/e9/Semicircle.svg b) List three items which operate on the principle “force acting on a current‐carrying conductor in a magnetic field”. - n.b these aren't homework questions, i'm doing an experiment tomorrow and this was in a book i'm reading (related to the experiment) I'm not sure how to solve the first one, can I do this mathematically??? or is it more of a geometrical problem? b - not sure if I know any practical applications of force on a current carrying wire, All i can think of is the magneto in microwaves anyone know any?