Induced emf in a solenoid from a current carrying wire nearby

AI Thread Summary
The discussion centers on the induced electromotive force (EMF) in a solenoid due to an external magnetic field from a nearby current-carrying wire. It is established that the induced EMF is a function of the solenoid's characteristics, particularly its radius, which influences the measured EMF. The relationship between solenoid current and induced EMF is highlighted, noting that increasing the solenoid current can decrease the magnetic flux through it, resulting in a lower EMF. The concept of inductance is also mentioned, indicating that the solenoid's design affects its ability to generate power from a fixed input. Understanding these relationships is crucial for calculating the current and EMF in practical applications.
silentstorm
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Say I have a solenoid that has a magnetic field Bo Sin(ωt) passing through its axis. What will be the EMF induced in the solenoid as a result ? I know it'll be a function of Cos (ωt) but I am more interested in how my choice of the solenoid will affect the EMF that I'll ultimately measure.

Thanks in advance!
 
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Calculate the fields separately and supperpose them. If the solenoid axis is parallel to z-axis, you can calculate the field for the wire first and add the solenoid field to its z-component.
 
Hassan, thanks for the response, but I don't understand what you mean. There is only one field here which is an external magnetic field. If you put a solenoid into a magnetic field, I am guessing the size (Radius) of the solenoid would affect the induced EMF ? I am interested in knowing what that relation would be.
 
silentstorm said:
Hassan, thanks for the response, but I don't understand what you mean. There is only one field here which is an external magnetic field. If you put a solenoid into a magnetic field, I am guessing the size (Radius) of the solenoid would affect the induced EMF ? I am interested in knowing what that relation would be.

Sorry I misread your question!

But your question,

Yes you are right. If it had no effect, the emf would be independant of the solenoid current. So by choosing a low resistance parallel with the slenoid we would get very high power from a fixed input power!

The effect is infact what we know as the inductace of the solenoid.
In order to calculate the current and emf when you have current in the coil, just imagine a voltage source in series with the inductance and the load. Calculation beomes simple then.

Added: The interaction is so that by increasing the solenoid current, the flux passing though it decrease and this results a lowe emf.
 
It may be shown from the equations of electromagnetism, by James Clerk Maxwell in the 1860’s, that the speed of light in the vacuum of free space is related to electric permittivity (ϵ) and magnetic permeability (μ) by the equation: c=1/√( μ ϵ ) . This value is a constant for the vacuum of free space and is independent of the motion of the observer. It was this fact, in part, that led Albert Einstein to Special Relativity.
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