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What is the electric potential when the electric field is zero?
When the electric field is zero, the electric potential is constant throughout the region and is independent of position. This means that the electric potential is the same at every point in the region where the electric field is zero.
What is the Condition for terminal voltage across a secondary cell to be equal to its emf?
The condition for the terminal voltage across a secondary cell to be equal to its emf is when there is no current flowing through the cell. When there is no current, there is no voltage drop across the internal resistance of the cell, and thus the terminal voltage equals the emf.
When a charge moves in the same direction as the magnetic field lines the magnetic force is?
Perpendicular to both the current and the magnetic field.
A wire in a lamp that is turned on would have a magnetic field around it?
Yes. Any current will produce a magnetic field. Note that such a field might be hard to detect, for example with a compass - since the AC current used in homes changes directions 50 or 60 times per second. Since this is much faster than the compass needle can follow, it will only show the average magnetic field, which is zero.
When there is a change in the magnetic field in a closed loop of wire?
An electromotive force (EMF) is induced in the wire loop due to Faraday's law of electromagnetic induction. This causes a current to flow in the wire loop, creating an electrical circuit. The induced current generates its own magnetic field that opposes the original change in magnetic field.
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.
Can you explain why there is an armature voltage even then the field current is zero in case of separately-excited dc generator?
if this happened it will be due to residual magentism and as soon as this magentism vanishes no voltage will be available , what iam saying can be interpreted mathematically first the generated emf across the armature is given by E= k* flux* speed it is clear due to this equation the emf is directly prportional to the flux which means if the flux is reduced so does the emf and the revers is true, the reduction may be lead to zero flux value and thus the emf (zero field current) secondly this emf covers the terminal voltage and the drop in armature winding if other possiple drops are ignored as E= terminal voltage + armature drop in this equation as E drops down as a result of reducing the flux and which in turn because of reduction in the field current , then right hand components will also drop down until both get zero values , so theoreyically no voltage will be exist at generator terminals when the field current comes to zero value, so the persistance of voltage is due to the residual field and will not last long
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.
When a loop of current carrying wire turns continuously in a magnetic field?
emf will be induced
What is the process of current in a circuit by changing a magnetic field?
When a magnetic field around a conductor is changed, it induces an electromotive force (EMF) in the conductor. This EMF causes a current to flow in the circuit, known as electromagnetic induction. The current will only flow when the magnetic field is changing, as stated by Faraday's law of electromagnetic induction.
How can you say that ac emf is induced in the coil?
When we place a current carrying conductor in a magnetic field emf is induced in a coil. we can knoe it by connecting voltmeter.
When current flows in a conductor a magnetic field is created. The created magnetic field cuts the conductor which creates a voltage in the conductor. What is this voltage called?
It's called back EMF or reverse EMF. The EMF is electro-motive force, or voltage. What is happening is that the original current flow creates a magnetic field. That field then induces a voltage that opposes the original voltage that is causing the current flow. This back EMF "resists" the original voltage's efforts to cause current flow. If the created magnetic field did not oppose the original "efforts" of the voltage source to make current flow, then it would aid that voltage to make current flow. We would then get something for nothing and perpetual motion would be possible. We can't do that.
How energy is transferred from stator to rotor?
when current is passing through the stator windings of motor magnetic field is develop ,due to it emf is produced inside the stator windings,that emf is further cuts the emf across stator due to which current flowing inside the rotor.
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.
Why induced emf alternates?
Here is A Simple answer for this question as you know that emf is induced in the conductor when there is change of flux linkage to the conductor which gives rise to the inducement of electric field in the conductor that provide drift velocity to the electrons hence emf is induced in the conductor but the last only till the change in flux in progress and becomes zero as soon as the flux linkages becomes constant hence we summaraize that for inducement of current there must be change in change of flux hence change in electric field that gives rise to allternating emf.
