The magnitude of the induced emf is proportional to the rate of change of the magnetic flux. The faster the coil turns, the larger the maximum value of the induced emf, since increased angular speed causes the magnetic flux to change more rapidly. … The induced emf goes through zero when the flux curve has zero slope.
Why is EMF zero when magnetic flux is maximum?
When the coil is upright there is no change in magnetic flux (i.e emf=0) because the coil isn’t ‘cutting across’ the field lines. The induced emf is zero when the coils are perpendicular to the field lines and maximum when they’re parallel.
Why is the EMF maximum when the plane of the armature is parallel to the magnetic field?
When the plane of the armature is parallel to the lines of force of magnetic field, the rate of change of magnetic flux linked with it is maximum. Therefore, the e.m.f. induced in the armature in this orientation is maximum.
Is magnetic flux always 0?
While the magnetic flux through a closed surface is always zero, the magnetic flux through an open surface need not be zero and is an important quantity in electromagnetism.
How magnetic flux can be zero when the magnetic field is not zero?
The magnetic flux is generated when a change in the magnitude and direction of the magnetic field occurs. If the magnetic field is parallel to the place of the area that is exposed, then the magnetic flux generated is zero when the magnetic field is not zero.
What is the maximum induced emf?
By Faraday’s law, the magnitude of the induced emf is equal to the rate of change of magnetic flux, so its maximum values occurs when the flux curve has its greatest slope. The induced emf goes through zero when the flux curve has zero slope.
What is the difference between EMF and induced emf?
Definition. It can be defined as the generation of a potential difference in a coil due to the changes in the magnetic flux through it. In simpler words, electromotive Force or EMF is said to be induced when the flux linking with a conductor or coil changes.
Why is EMF induced in an AC generator?
The armature is arranged so that it can rotate freely in the magnetic field. When armature turns then due to change in magnetic flux an induced e.m.f is produced. Factors on which e.m.f depends: The strength of e.m.f can be increased by, Increasing the number of turns of coil. Increasing the velocity of coil.
What happens when a block of metal is kept in a varying magnetic field?
When a block of metal is kept in a varying magnetic field then Eddy current is produced. An eddy current is a current set up in a conductor in response to a changing magnetic field. They flow in closed loops in a plane perpendicular to the magnetic field.
What is a magnetic field definition?
: the portion of space near a magnetic body or a current-carrying body in which the magnetic forces due to the body or current can be detected.
Can you have negative EMF?
The voltage is not negative, always. The negative sign in Faraday’s law (Lenz’s law) does not mean that the EMF (or current) always points in some “negative” direction. It means that the current always flows in a way to oppose the change in flux, which is nicely illustrated in that video clip.
What is motional EMF?
About Transcript. An emf induced by motion relative to a magnetic field is called a motional emf. This is represented by the equation emf = LvB, where L is length of the object moving at speed v relative to the strength of the magnetic field B.
Can the magnetic flux be negative?
Yes, magnetic flux can be negative. It just depends on where the field is going. Say there is a sheet and magnetic field is going through it from front to the back, we can call the flux there as positive and negative when it’s the other way round.
What is self induced emf?
Definition: Self-induced emf is the e.m.f induced in the coil due to the change of flux produced by linking it with its own turns. This phenomenon of self-induced emf can be further understood by the following example given below: Consider a coil having N number of turns as shown in the above figure.
How do you induce EMF?
An emf is induced in the coil when a bar magnet is pushed in and out of it. Emfs of opposite signs are produced by motion in opposite directions, and the emfs are also reversed by reversing poles. The same results are produced if the coil is moved rather than the magnet—it is the relative motion that is important.
What is the basic cause of induced emf?
The most basic cause of an induced EMF is change in magnetic flux. 2. Placing a current carrying coil that is moving constantly in a stable and static magnetic field. This will cause a change in the area vector and hence, EMF will be generated.