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What is the relationship between current and current density?
Current (I) is measured in amperes, which is an SI Base Unit, defined in terms of the force (expressed in newtons) between two, parallel, current-carrying conductors.Current is the rate at which electric charge (Q) flows. Electric charge is measured in coulombs, which is an SI Derived Unit, defined in terms of current and time (t) the ampere and the second. That is: Q = I t.So a 'coulomb' is a special name given to an 'ampere second'.
What is difference between induced voltage and induced current?
Just as a current flowing through a wire will produce a magnetic field, so a wire moving through a magnetic field will have a current flowing through it. This is called electromagnetic induction and the current in the wire is called induced current. A stationary wire in the presence of a changing magnetic field also has an induced current. A changing magnetic field can be produced either by moving a magnet near to the stationary wire or by using alternating current. A stationary wire in a magnetic field which is not changing will have no current induced in it. You will sometimes see this effect described as induced voltage. Strictly speaking, you will only get an induced current in the wire if it is part of a complete circuit. A wire which is unconnected at both ends will have a difference in voltage between the ends (a potential difference) but current can only flow when the wire is in a circuit. Induced current is used in electricity generation and transformers.Another AnswerThere is no such thing as an 'induced current', only an 'induced voltage'. Current will flow only if the conductor into which the voltage is induced forms part of a closed circuit.
What is meant by mutual inductance?
Mutual inductance is where two electrically separate coils of wire are either close to each other or share the same core. An alternating current flowing in one of the coils will 'induce' a current to flow in the other coil. For example by using coils wound with wire of the correct length and thickness, a transformer fed by mains electricity can by mutual inductance, produce a lower voltage to power your PC or radio.CommentMutual inductance occurs when a changing current (a.c. or d.c.) flowing in one coil induces a voltage (not a current!) into a second coil.
Why DC current is not used in transformers?
A transformer couples energy from the input winding to the output winding by means of a changing magnetic field. AC current is a changing electric field, which produces changing magnetic fields when put to a wire and so is ideal for a transformer. This fact is why virtually all power distibution is AC. If DC were put to a transformer, once the winding magnetized in a fraction if a second, the current drawn would be so much it would blow the circuit. In other words, you can not use DC on a transformer because the transformer would be blown up by it.Another AnswerWhen any current passes through any conductor, invisible Electro-Magnetic fields are produced in the immediate space around the conductor; the strength and distance of these fields are proportional to the amount of current that passed through the conductor. The electric field is in the plane of the conductor while the magnetic field is perpendicular to the conductor. If the current is DC, the fields grow to their maximum and stay there. If the DC source is removed, the fields collapse. If there is enough current passing through the conductor, the fields will expand, break away from the conductor, and continue to propagate through space at the speed of light. This is the principal of a radio and TV station antenna. This propagation is also a direct loss of source energy.Induction is described as the relative motion of a conductor through a magnetic field. This can either be the magnetic field in motion with a fixed conductor, or a fixed magnetic field with the conductor in motion. Either of these conditions will induce an electric current in the conductor.Transformers work under the principal of induction. There is a primary coil and a secondary coil in transformers. The core of the transformer can be air, iron powder, or solid iron; among other material configurations. The ratio of the windings from the primary to the secondary determines if the voltage will be stepped up or down in the secondary. If there are twice as many windings in the secondary as are in the primary, the output of the secondary will be twice the voltage and half the current of the primary. If there are twice as many windings in the primary as are in the secondary, the output of the secondary will be half the voltage and twice the current of the primary. This rule does not take into consideration any loss in the field generation due to: counter EMF, impedance, propagation, etc.Since the transformer relies on the principal of induction, there has to be a relative motion between the magnetic field and the coil. If you apply a DC source to the primary of the transformer while watching the output of the secondary, what you'll see is a spike on the secondary where the magnetic field in the primary expanded, cutting through the secondary coil, but did not contract. This does not constitute the fundamental requirements of sustained induction. The above contributor is correct when saying the primary would draw as much current as the DC source could provide, usually ending in some catastrophic failure. The reason the DC current could run away is there is minimal resistance in the primary coil wire to DC current.There is, in fact, a form of resistance to an AC source applied to a coil. This is known as impedance and is caused by some of the factors mentioned above, mainly "Counter EMF". Counter EMF is a phenomenon produced because one loop of the winding is lying next to the next loop in the winding; when current is sent through the coil. When the magnetic field in the first loop starts to expand, it does so in a particular direction. The "Right Hand Rule of Thumb" can be applied to this scenario to determine which direction the magnetic field is traveling around the wire. Imagine using your right hand to wrap your fingers around a wire with your thumb pointing in the direction of current flow. Your fingers point in the direction of the magnetic field. When this magnetic field expands through the next loop in the coil, it induces a small amount of current in the opposite direction of the source current, which acts as a dynamic resistance to the main current source. This impedance is why current lags voltage by 90° in an inductive circuit.This subject is both broad and deep.
How does the left hand rule apply alternating current generator?
your thumb will point to the diretion of the rotation...and you forefinger will point to the direction of the magnetic fluxAnswerFleming's Left-Hand Rule applies to motors when using 'conventional flow' and to generators when using 'electron flow'. So, assuming you are talking about electron flow, the thuMb indicates the direction of Motion of the conductor relative to the flux, the First finger indicates the direction of the magnetic Field (north to south), and the sEcond finger indicates the direction of the E.m.f. induced into the conductor. This applies whether the generator as an a.c. machine or a d.c. machine.
What is key when using a magnet and a conductor to induce a current in the current?
Motion
What is the key using a magnet and a conductor to induce a current in the conductor?
A changing magnetic field, in the conductor, can induce a voltage (and, under the correct conditions, that in turn will result in a current). In the case of a permanent magnet, either the magnet or the conductor has to move.
What is the key when using a magnet and a conductor to induce a current in the conductor?
Motion
How can you induce current in a wire using a permanent magnet?
By moving the wire perpendicular to the magnetic field lines created by the permanent magnet, you can induce a current in the wire through electromagnetic induction. The changing magnetic field as the wire moves induces an electric field, resulting in a current flow in the wire according to Faraday's law.
How do you strengthen a magnet?
You can strengthen a magnet by exposing it to a strong magnetic field, either by placing it near another strong magnet or using an electromagnet. You can also induce a current in the magnet by tapping it with a hammer or passing an electric current through it to realign its magnetic domains and increase its strength.
Can we make magnet without using magnetic material?
Yes. Electromagnets don't require a magnetic material; they just require a conductor and an electric current.
What are ways to magnetize something?
Some ways to magnetize something include stroking it with a magnet in the same direction repeatedly, exposing it to a strong magnetic field, or using an electric current to induce magnetism temporarily.
How can a magnet be used to create an electric current using the words magnetic field attract repel magnetic poles?
A magnet cannot use words to create an electric current. A moving magnet will induce electric current in adjacent conductors. This is usually described in terms of the rate that magnetic flux lines connecting the opposite poles of the magnet "cut" the conductors. The more flux lines cutting the conductors per second, the more current induced.
How can one create magnetic energy?
One can create magnetic energy by using a magnetic material, such as iron or a magnet, and moving it near a conductor, such as a wire. This movement of the magnetic material near the conductor induces an electric current, which in turn generates magnetic energy.
How does a permanent magnet generator work to produce electricity?
A permanent magnet generator works by using the magnetic field of permanent magnets to induce an electric current in a coil of wire. As the magnets rotate, they create a changing magnetic field that causes electrons in the wire to move, generating electricity through electromagnetic induction.
How can electricity produce by using magnet?
Electricity is generated when a piece of conductive metal (such as copper) is passed through a magnetic field (or if the magnetic field is moved around the metal). A generator will have a copper wire in the center, surrounded by a magnet shaped like a torus (donut shaped, wire is in the hole in the middle). The wire is stationary. Electricity is generated when the magnet is spun (moving the magnetic field around the wire). This will generate an AC current (alternating current).
How was current produce or induced?
Current can be induced in a conductor through electromagnetic induction, where a changing magnetic field causes a flow of electric current. This can be achieved by moving a magnet near a conductor or by varying the current in one nearby. Alternatively, current can be produced by a voltage source such as a battery or generator that creates a potential difference to drive the flow of electrons.
