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Current flow is from positive to negative. Use the left hand rule for finding the north and south poles. Grab the coil in your left hand, with your fingers wrapped around the coil in the direction of the current flow. Your thumb will then point toward the north pole of the coil.

Reverse the positive - negative connections to the coil and the north - south poles will change ends. The left hand rule will still be in effect as the current will now be flowing in the reverse direction as it was in the first connection.

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βˆ™ 10y ago
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βˆ™ 9y ago

The direction of the current does.

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βˆ™ 13y ago

The polarity (in regards to magnetism (north and south)) is determined by the direction of the current flow.

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Q: How the direction of EMF depends on the direction of current?
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What are the factors determining the size and direction of a generated emf?

There are three factors for determining the size and direction of the emf generated from an AC generator. the strength of the magnetic field, the size of the field, and the speed of the rotation combine to determine this.


Why does the rotation of the motor reversed when change the polarity across the main winding coil?

When changing the auxilary face winding connection the current flow in the winding is changed so that the rotating emf direction is changed . Thats why the motor rotates in opposite direction.


Why does the induced emf known as back emf?

In a dc motor the voltage generated in the armature acts against the supply voltage. The current is the voltage difference divided by the armature resistance. If the rotor is turned faster so that the back emf exceeds the supply voltage, the current goes the other way and the motor has become a generator.


Difference between back EMF and induced EMF?

An induced electromotive force (emf) is an induced voltage. Voltage (emf) causes current flow, and this induced voltage will cause a current that is called the induced current.We might also add that the induced current will cause a magnetic field to expand about the current path, and this field will "sweep" the conductor. The sweeping of the conductor by that expanding magnetic field will set up an emf that will oppose the emf that was creating it.CommentTechnically, there is no such thing as an 'induced current'. It is voltage that is induced. Any current flows as a result of that induced voltage being applied to a load. But that current is certainly NOT induced!


Does motional emf call induced emf?

yes indused emf is also called motional emf. If an open coil is subjected to a variable magnetic field, at the ends of the coil a potential difference is induced which is called induced emf. If a coil is connected to an emf source and switched on, the rising current will produced an variable magnetic field which in turn produces an emf. It is called back emf.

Related questions

Is emf a scalar or vector quantity?

Emf has direction within a current loop, though it is not scalar. It's a bit between though as direction should be otherwise accounted for when discussing induced Emf. Not quite either.


What is the statment of lenz law?

The direction of an induced emf or current is such that the magnetic field created by the induced current opposes the change in magnetic flux that created the current.


What does the lenz law state?

The direction of an induced emf or current is such that the magnetic field created by the induced current opposes the change in magnetic flux that created the current.


Does current depends on its resistance?

The current flow in an electrical circuit depends on the applied electromotive force (EMF, measured in volts), and the total resistance along the entire circuit. Rising EMF or dropping resistance cause increased current flow


What is the emf induced at zero field current.and what does it signify?

EMF is the voltage across a coil (or motor) due to changes in the magnetic field. If you change the current the coil will generate a voltage (in the opposite direction of the current). So it is not the field but the change that matters.


What are the factors determining the size and direction of a generated emf?

There are three factors for determining the size and direction of the emf generated from an AC generator. the strength of the magnetic field, the size of the field, and the speed of the rotation combine to determine this.


Why does the rotation of the motor reversed when change the polarity across the main winding coil?

When changing the auxilary face winding connection the current flow in the winding is changed so that the rotating emf direction is changed . Thats why the motor rotates in opposite direction.


The direction of a magnetic field produced by an electric current depends on the direction of the what?

Flow of the current.


Does the direction of emf provided by the battery depend on the direction of the current flow through the battery?

Within a source of emf ( like a battery) a chemical reaction occurs which moves the mobile charge carriers from a region where they have low electric potential energy to a region where they have a higher electric potential energy.(like water raised by a pump from lower gravitational potential to a higher gravitaional potential at the cost of electricity etc). However, in the circuit when connected to a load, the current flows from higher potential to lower potential (like water flows from the water tank at the roof to the tape in the kitchen). To summarize, the electric current flows from negative to the positive terminal in the outer load circuit while in the battery (source of emf) the current by positive ions flows from negative to the positive terminal at the cost of energy. Therefore, the direction of emf provided by a battery doesn’t depend on the direction of the current flowing through the battery.


What would happen if you generated gravity in a electromagnetic field?

The earth has gravity and an outer EMF. So the forces coexist. An electrical cable has a gravitational force but extremely small. When a current flows through the cable an electromagnetic field is also created (EMF). An EMF can conversely generate an electric current. The EMF pushes the electrons along the cable in one direction. Gravitational force exists between the atoms. The forces can thus vectorially added.


Is emf current greater than current?

EMF is electromotive force. It is another name for voltage. Voltage is electric potential in joules per coulomb. Current is electric flow, in amperes. Amperes are coulombs per second. Voltage and current are not the same thing, and "emf current", or "voltage current" does not make sense.


Why does the induced emf known as back emf?

In a dc motor the voltage generated in the armature acts against the supply voltage. The current is the voltage difference divided by the armature resistance. If the rotor is turned faster so that the back emf exceeds the supply voltage, the current goes the other way and the motor has become a generator.