Which of the following explains why an actual cost might differ from a projected cost? -the desired item goes on sale. -the item is no longer available and a replacement must be found. -the price of an item suddenly increases. -all of the above

the direction of the magnetic field produced by an electric current will change when the direction of the electric current changes. for example : if a current is flowing in a straight length of wire, the magnetic field is described by a concentric circle (using right-hand rule).