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what is faraday law how to explain left and right laws

what is faraday law how to explain
left and right laws
 

Grade:10

2 Answers

Nishant Vora IIT Patna
askIITians Faculty 2467 Points
7 years ago
Faraday’s law

Faraday's lawof induction is a basiclawof electromagnetism predicting how a magnetic field will interact with an electric circuit to produce an electromotive force (EMF)—a phenomenon called electromagnetic induction.


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jyoti bhatia
202 Points
7 years ago
Faraday’s Law of Induction describes how an electric current produces a magnetic field and, conversely, how a changing magnetic field generates an electric current in a conductor. Michael Faraday gets credit for discovering magnetic induction in 1830.
Magnetic induction makes possible the electric motors, generators and transformers that form foundation of modern technology. By understanding & using induction, we have an electric power grid.
Faraday’s law was later incorporated into more comprehensive Maxwell’s equations. Maxwell’s equations explained relationship between electricity and magnetism, essentially uniting them into a single electromagnet force and describing electromagnetic waves that make up radio waves, visible light and X-rays.
If we run an electric current through a wire, it will produce a magnetic filed around the wire. The direction of this magnetic field can be determined by right-hand rule. If you extend your thumb and curl the fingers of your right hand, your thumb points in positive direction of magnetic field coming out of the center of loop, while your fingers will point in positive direction of the current in the loop.
If you bend the wire into a loop, magnetic field lines will bend with it, forming a toroid or doughnut shape. In this case, your thumb points in north direction of magnetic field coming out of the center of loop, while your fingers will point in positive direction of current in the loop.
If we run a current through wire loop in a magnetic field, interaction of these magnetic fields will exert a twisting force or torque, on the loop causing it to rotate. But, it will only rotate so far until magnetic fields are aligned. If we want loop to continue rotating, we have to reverse the direction of current, which will reverse direction of magnetic filed from loop. The loop will then rotate 180 degrees until its field is aligned in other direction. This is the basis for electric motor.
Conversely, if we rotate a wire loop in a magnetic field, the field will induce an electric current in the wire. Direction of current will reverse every half turn, producing an alternating current. This is the basis for electric generator. It is not the motion of wire but rather opening and closing of loop with respect to direction of field that induces the current. When loop is face-on to the field, maximum amount of flux passes through loop. However, when loop is turned edge-on to the field, no flux lines pass through the loop. It is this change in amount of flux passing through loop that induces the current. Another experiment one can perform is to form a wire into a loop and connect ends to a sensitive current meter or galvanometer. If we push a bar magnet through loop, the needle in galvanometer will move, indicating an induced current. but once we stop motion of magnet, current returns to zero. The field from magnet will only induce a current when it is increasing or decreasing. If we pull magnet back out, it will again induce a current in the wire but this time it will be in opposite direction.
 
 

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