A student was asked to perform an experiment to study the force on a current carrying conductor in a…
A student was asked to perform an experiment to study the force on a current carrying conductor in a magnetic field. He took a small aluminum rod AB, a strong horse shoe magnet, some connecting wires, a battery and a switch and connected them as shown. He observed that on passing current, the rod gets displaced. On reversing the direction of current, the direction of displacement also gets reversed. On the basis of your understanding of this phenomenon, answer the following questions :
(a) Why does the rod get displaced on passing current through it ?
(b) State the rule that determines the direction of the force on the conductor AB.
(c) (i) If the U shaped magnet is held vertically and the aluminum rod is suspended horizontally with its end B towards due north, then on passing current through the rod from B to A as shown, in which direction will the rod be displaced ?
(ii) Name any two devices that use current carrying conductors and magnetic field.
Solution
(a) A force is exerted on the current carrying rod when it is placed perpendicular to the magnetic field.
(b) Fleming's left-hand rule : Stretch the thumb, forefinger and middle finger of your left-hand such that they are mutually perpendicular. If the first finger points to the direction of magnetic field and the second finger in the direction of current, then the thumb will point in the direction of motion or the force acting on the conductor.
(c) (i) Towards left or towards west / Into U shape magnet
(ii) Electric motor/ electric generator/ loudspeakers/ microphones/ electrical measuring instruments (any two)
