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Magnetic Effects of Electric Current 107, , Fleming’s Left Hand Rule, Using the same set up (as in Activity 4.3) it can be shown that displacement of the rod is, maximum when it is at right angles to the direction of magnetic field or we can say that, magnetic field of the U-shaped magnet is perpendicular to the current carrying conductor, (rod). No force acts on the rod when the magnetic field becomes parallel to the current, carrying conductor., So we can say that ‘force’ on a current, carrying conductor, (i) is always perpendicular to the plane, containing the conductor and the, direction of the field in which it is, placed, (ii) is maximum when the conduction is, at right angles to the magnetic field., The direction, magnetic field, force, on conductor and current are governed, according to Flemings Left Hand Rule (Fig., 4.15)., , Stretch the thumb, the forefinger and middle finger of your left hand such that they are, mutually perpendicular to each other. Pe ree aie ditection of the magnetic, Field and the middle finger in the direction of the Current, then the thumb will point in, the direction of force acting on the conductor [Remember Fleming’s Left Hand Rule is, used to find out the direction of force.], , , , Movement, , Force, , Field, , , , , , Factors Affecting the Force, The force experienced by the current carrying conductor ‘AB’ when placed in a uniform, magnetic field (i.e., the displacement of a conductor) depends on:, , 1. The strength of the electric current flowing through the conductor. F ~ J; if a large, current flows through the conductor, it experience a large force, i.e., magnitude of the, force will be greater., , 2. The length of the conductor. F « L; greater the length of the conductor greater will, be the force acting on it., , 3. The strength of the magnetic field. F « B; stronger the magnetic field in which the, conductor is placed stronger will be the force acting on the conductor., , , , Q.1. How is the direction of force acting on a current carrying conductor kept in a magnetic field