Can there be an induced emf in a circuit at an instant when the magnetic flux through the circuit is zero?
The induced emf in a circuit is proportional to the magnetic flux through the circuit. There can be an induced emf at an instant when the flux through the circuit is zero.
What are the factors that affect the magnitude of an induced emf in a coil of wire?
The induced e.m.f. is proportional to the number of turns in a coil. The speed at which the conductor moves through the magnetic field. The length of the conductor. The rate at which the conductor cuts the magnetic lines of force.
Does an induced emf always cause a current to flow?
The direction of the induced emf drives current around a wire loop to always oppose the change in magnetic flux that causes the emf. If it were not the case that the induced field opposes the change in the flux, the magnet would be pulled in produce a current without anything having done work.
When conductor moves through a non uniform magnetic field the electric current induced is called?
An electric current induced within the body of a conductor when that conductor either moves through a nonuniform magnetic field or is in a region where there is a change in magnetic flux. It is sometimes called Foucault current.
Does the induced emf always act to decrease the magnetic flux?
No, when the magnetic flux decreases, the induced emf act to increase it.
Does the change in magnetic flux induce current or emf?
Due to change in magnetic flux, e.m.f. is always induced, but induced current will flow only when the circuit is complete.
What affects induced emf?
Which two factors influence the emf induced in the secondary windings of a transformer?
The factors on which the magnitude of the induced emf in the secondary coil of the transformer depends on:
- The relative positioning of the two coils:
- Positioning them on a common soft iron core:
- Increasing the number of turns:
What are different ways by which emf can be induced in a conductor?
There are therefore three ways an emf can be induced in a loop: Change the magnetic field. Change the area of the loop. Change the angle between the field and the loop.
Is motional emf and induced emf same?
By Faraday’s Law, you get an induced emf whenever there’s a changing magnetic flux through a loop. If the changing emf is due to some kind motion of a conductor in a magnetic field, you would call it a “motional emf”.
How can Earth’s magnetic field be used to induce emf in a coil?
When does a coil experience an induced current when magnetic field varies?
A coil experiences an induced current when the magnetic field passing through it varies. (a) When the magnet moves toward the coil the current is in one direction. (b) No current is induced while the magnet is held still.
What is the difference between magnetic flux and current?
Change in the number of field lines through a coil gives a current. Number of field lines through a coil is called magnetic flux. When a loop is moved parallel to a uniform magnetic field, there is no change in the number of field lines passing through the loop and no induced current.
What happens when the magnetic field of a circuit is changed?
While the magnetic field is being changed, the magnetic flux is being increased out of the page. According to Lenz’s law, the emf induced in the loop by this changing flux produces a current that sets up a field opposing the change.
How does the direction of induced EMF affect current?
The direction of the induced EMF will control the direction of the induced current. The direction of the induced EMF follows from Lenz’s Law. Lenz’s Law. The current that is induced in a coil (due to a magnetic flux change through the coil) will always be such that it opposes the change that caused it.