In: Physics
A straight metal wire is placed between the poles of a magnet, as shown in the figure. Magnetic field is uniform in the space between the poles. If there is a current I flowing through this wire in the direction from C to A, what is the direction of the magnetic force acting on the wire?
The picture is not attached, But you can solve it using Fleming's Left Hand rule. It says that stretch the forefinger, middle finger and thumb in mutually perpendicular direction, then the forefinger indicates the direction of magnetic field, middle finger indicates the direction of flow of current and thumb indicates the direction of motion of the conductor or direction of magnetic force on the conductor.
So if the north and south pole of magnet is shown in picture, then point your forefinger to the south indicating direction of magnetic field from north to south.
Since the current is flowing from C to A, point your middle finger towards A, indicating current is from C to A.
Now stretch the thumb such that all the three fingers are in mutually perpendicular direction as shown in the figure. The direction in which thumb points indicates the direction of magnetic field.