(a) A current-carrying conductor is placed perpendicularly in a magnetic field. Name the rule which can be used to find the direction of force acting on the conductor.(b) State two ways to increase the force on a current-carrying conductor in a magnetic field.
(c) Name one device whose working depends on the force exerted on a current-carrying coil placed in a magnetic field.

According to Fleming's left-hand rule, when left hand's thumb, forefinger (or, index finger) and centre finger (or, middle finger) are held mutually perpendicular to one another and adjust in such a way that the forefinger points in the direction of the magnetic field, and the centre finger points in the direction of the current, then the direction in which thumb points, gives the direction of force acting on the conductor.