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If ΔΦ B is positive, the direction of the emf is the same as that of the curved fingers (yellow arrowheads). If ΔΦ B is negative, the direction of the emf is against the arrowheads. [22] It is possible to find out the direction of the electromotive force (emf) directly from Faraday’s law, without invoking Lenz's law.
When a conductor such as a wire attached to a circuit moves through a magnetic field, an electric current is induced in the wire due to Faraday's law of induction. The current in the wire can have two possible directions. Fleming's right-hand rule gives which direction the current flows.
In mathematics and physics, the right-hand rule is a convention and a mnemonic, utilized to define the orientation of axes in three-dimensional space and to determine the direction of the cross product of two vectors, as well as to establish the direction of the force on a current-carrying conductor in a magnetic field.
A flow of positive charges gives the same electric current, and has the same effect in a circuit, as an equal flow of negative charges in the opposite direction. Since current can be the flow of either positive or negative charges, or both, a convention is needed for the direction of current that is independent of the type of charge carriers ...
Illustration of the "reference directions" of the current (), voltage (), and power () variables used in the passive sign convention.If positive current is defined as flowing into the device terminal which is defined to be positive voltage, then positive power (big arrow) given by the equation = represents electric power flowing into the device, and negative power represents power flowing out.
Using the right hand rule to find the direction of the magnetic field. The direction of the magnetic field at a point, the direction of the arrowheads on the magnetic field lines, which is the direction that the "north pole" of the compass needle points, can be found from the current by the right-hand rule.
Fleming's rules are a pair of visual mnemonics for determining the relative directions of magnetic field, electric current, and velocity of a conductor. [1]There are two rules, one is Fleming's left-hand rule for motors which applies to situations where an electric current induces motion in the conductor in the presence of magnetic fields (Lorentz force).
On the far side of the figure, the return current flows from the rotating arm through the far side of the rim to the bottom brush. The B-field induced by this return current opposes the applied B-field, tending to decrease the flux through that side of the circuit, opposing the increase in flux due to rotation. On the near side of the figure ...