Induced emf in a falling wire aligned with Earth's magnetic field components

In summary, the conversation discusses whether a piece of metallic wire, when dropped from a height and aligned in either the geographic east-west or north-south direction, would have an induced emf or not due to the Earth's magnetic field. The equation E= - d(phi)/dt is mentioned, where phi represents the flux intercepted by the wire. It is confirmed that there will be an induced emf in both cases due to the perpendicular component of the Earth's magnetic field. It is also clarified that the horizontal component of the Earth's magnetic field, in the plane of the magnetic meridian, is what is intercepted by the wire and leads to the induced emf.
  • #1
kihr
102
0

Homework Statement



Whether a length of metallic wire, if placed in the geographic (a) east-west, and (b) north-south directions, and dropped freely from a height, would have an induced emf or not.

Homework Equations



E= - d(phi)/dt, where phi = flux intercepted by wire

The Attempt at a Solution



The magnetic field of the Earth has a vertical and a horizontal component, both of which lie on the magnetic meridian. The horizontal component (in the plane of the magnetic meridian) would further have components along the geographic N-S and E-W directions depending on the magnetic declination at the given point on the Earth's surface. Thus for (a) the falling piece of wire would cut the horizontal component of the Earth's magnetic field acting along the geographic N-S direction, and an emf would be induced. For (b) the wire would cut the horizontal component of the Earth's magnetic field acting along the geographic E-W direction, and here again an emf would be induced in the wire.

I would appreciate if the correctness of above could be confirmed. Thanks.
 
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  • #2
Basically what you are saying is that the magnetic north and geographic north do not align, so in either option there is some perpendicular component of the field, so there is an induced emf, which is correct.
 
  • #3
The perpendicular component of the Earth's magnetic field is not intercepted by the wire irrespective of whether it is aligned along the geographic N-S or E-W direction. However, the component of the Earth's horizontal magnetic field (i.e. in the plane of the magnetic meridian) along the geographic N-S and E-W directions do get intercepted by the falling wire aligned along the E-W and N-S directions respectively. This gives rise to the induced emf. I hope I have been able to make my point of view clear. Thanks.
 

What is electromagnetic induction and how does it work?

Electromagnetic induction is the process of generating electricity by moving a conductor through a magnetic field. This movement creates a change in the magnetic field, which in turn produces an electric current in the conductor.

Who discovered electromagnetic induction?

Electromagnetic induction was discovered by Michael Faraday in 1831. He observed that a changing magnetic field could induce an electric current in a wire.

What is the difference between mutual and self-induction?

Mutual induction occurs when two separate coils are placed near each other, and a changing current in one coil induces a current in the other coil. Self-induction, on the other hand, occurs when a changing current in a single coil induces a voltage in that same coil.

What are some practical applications of electromagnetic induction?

Electromagnetic induction has many practical applications, including generators, transformers, and electric motors. It is also used in wireless charging, electromagnetic levitation, and electromagnetic braking systems.

What factors affect the strength of the induced current in electromagnetic induction?

The strength of the induced current depends on several factors, including the strength of the magnetic field, the speed at which the conductor moves through the field, the angle between the conductor and the magnetic field, and the number of turns in the conductor. It also depends on the material and thickness of the conductor, as well as any external resistances in the circuit.

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