What is the EMF generated in a Straight Conductor?

In summary, the EMF generated in a straight conductor of length L placed in a time varying magnetic field B as shown in the figure is -B.L.ω.cosωt.
  • #1
kpsr
11
0

Homework Statement


What is the EMF generated in a straight conductor of length L placed in a time varying magnetic field B as
shown in the below figure..
Img_zps0twbecya.jpg


Homework Equations

The Attempt at a Solution


Time varying magnetic field is B.cosωt,
EMF = (d/dx)(B.L.cosωt) = -B.L.ω.cosωt
I don't know this result true or not Please correct me..
 
Physics news on Phys.org
  • #2
kpsr said:

Homework Statement


What is the EMF generated in a straight conductor of length L placed in a time varying magnetic field B as
shown in the below figure..
Img_zps0twbecya.jpg


Homework Equations

The Attempt at a Solution


Time varying magnetic field is B.cosωt,
EMF = (d/dx)(B.L.cosωt) = -B.L.ω.cosωt
I don't know this result true or not Please correct me..
What is the original vector equation that is usually used to calculate this type of problem? :smile:
 
  • #3
berkeman said:
What is the original vector equation that is usually used to calculate this type of problem? :smile:
In my above attempt I have used the transformer emf formula, in that formula I just used a straight conductor instead of a coil..
I saw that result in a website a long time ago and that site is not available right now. that's why i am not sure about the result.
 
  • #4
kpsr said:
In my above attempt I have used the transformer emf formula, in that formula I just used a straight conductor instead of a coil..
I saw that result in a website a long time ago and that site is not available right now. that's why i am not sure about the result.
Assume that you just have a rod without a voltmeter. You have "Free" electrons inside the wire.
Okay so it is stationary right? What does that tell you about the forces acting on the electrons?
If I calculate the work done by these forces it is equal to the voltage so what do you find?Now let's say you want to check your results in a lab, You brought a voltmeter and connected it to the rod. Would you expect the result to be the same as the above? and Why? What law should you used here?
 
  • Like
Likes rude man and berkeman
  • #5
kpsr said:
In my above attempt I have used the transformer emf formula, in that formula I just used a straight conductor instead of a coil..
I saw that result in a website a long time ago and that site is not available right now. that's why i am not sure about the result.
That is not the fundamental vector equation for this problem. If you are not familiar with that equation, it will take a bit more work to help you with this. What class is this for? What level in university or high school? :smile:
 
  • #6
I have searched a lot, Please check the file from here ...
In this file Case(i) is the problem i mentioned in my post,
Please explain/elaborate Case(i) emf for me.
 
Last edited:
  • #7
kpsr said:
Please explain/elaborate Case(i) emf for me.
Since this is a schoolwork-type question, our site rules require us to try to get you to figure it out on your own, rather than giving you the answer.
kpsr said:

The Attempt at a Solution


Time varying magnetic field is B.cosωt,
EMF = (d/dx)(B.L.cosωt) = -B.L.ω.cosωt
I don't know this result true or not Please correct me..
You didn't answer my question yet -- do you know the general vector equation that is used to calculate the EMF of a wire in a changing magnetic field? That is how you should approach this problem, rather than using simplifications of the equation like you posted above. If you're not sure which equation it is, just Google for calculate EMF in a wire from a changing magnetic field... :smile:
 
  • #8
berkeman said:
You didn't answer my question yet -- do you know the general vector equation that is used to calculate the EMF of a wire in a changing magnetic field? That is how you should approach this problem, rather than using simplifications of the equation like you posted above. If you're not sure which equation it is, just Google for calculate EMF in a wire from a changing magnetic field... :smile:
I googled a lot and every time what i can found is the emf generated only for a conductor coil/loop in a changing magnetic field (B.cosωt),
and that general vector equation is
Emf_zpsbcl1aoox.jpg

or
Emf-1_zpsa2tcyajn.jpg

Here N is the number of turns in coil, A is the area of the coil and hence B.A is the flux Φ linked with that coil.
But what i am talking about a straight conductor with N almost 1 and there is no area A except length L.
that's why i replaced the flux BA from above equations with BL ,correct my approach...
 
  • #9
kpsr said:
I googled a lot and every time what i can found is the emf generated only for a conductor coil/loop in a changing magnetic field (B.cosωt),
and that general vector equation is
Emf_zpsbcl1aoox.jpg

or
Emf-1_zpsa2tcyajn.jpg

Here N is the number of turns in coil, A is the area of the coil and hence B.A is the flux Φ linked with that coil.
But what i am talking about a straight conductor with N almost 1 and there is no area A except length L.
that's why i replaced the flux BA from above equations with BL ,correct my approach...
Good. So if there is no area enclosed, the induced EMF would be... :smile:
 
  • #10
berkeman said:
Good. So if there is no area enclosed, the induced EMF would be... :smile:
the induced EMF would be zero.. But that must be not correct, as from the working principle of transformers there must be an emf given by the Case(i) from the file or may be else, that what really confusing me, please clarify it..
 
  • #11
kpsr said:
the induced EMF would be zero.. But that must be not correct, as from the working principle of transformers there must be an emf given by the Case(i) from the file or may be else, that what really confusing me, please clarify it..
What is "Case(i)"? A transformer has an EMF induced by the changing magnetic field that pierces the coils because the coils have area. So the B dot dA term in the equation is non-zero...
Emf-1_zpsa2tcyajn.jpg
 
  • #12
berkeman said:
What is "Case(i)"? A transformer has an EMF induced by the changing magnetic field that pierces the coils because the coils have area. So the B dot dA term in the equation is non-zero...
Emf-1_zpsa2tcyajn.jpg
The Case(i) transformer Emf across a straight conductor of length L due to non-uniform magnetic field (B.cosωt) is
Emf-2_zps2se2jk72.jpg

Here also changing magnetic field (B.cosωt) pierces the straight conductor of length L, it's not a coil so there is only L in formula not area dA.
the above formula is not my own it's derived from this file here ...
my only question is that the result from the file is correct or not..?
 

Related to What is the EMF generated in a Straight Conductor?

1. What is EMF?

EMF stands for electromagnetic force or electromotive force. It is the force that causes the motion of charged particles in an electric field.

2. How is EMF generated in a straight conductor?

EMF is generated in a straight conductor when there is a change in the magnetic flux through the conductor. This can be achieved by moving a magnet near the conductor or by changing the current flowing through the conductor.

3. What factors affect the amount of EMF generated in a straight conductor?

The amount of EMF generated in a straight conductor depends on the strength of the magnetic field, the length of the conductor, and the speed at which the conductor moves through the magnetic field. It also depends on the material of the conductor and its resistance.

4. Can EMF generated in a straight conductor be harmful?

In most cases, the EMF generated in a straight conductor is not harmful to humans. However, exposure to high levels of EMF for long periods of time may have negative health effects. It is important to follow safety guidelines and limit exposure to high levels of EMF.

5. How is EMF generated in a straight conductor used in everyday life?

EMF generated in a straight conductor is used in a variety of everyday devices, such as generators, motors, and transformers. It is also used in wireless communication technologies, such as radios and cell phones. In addition, EMF generated in a straight conductor is used in medical imaging techniques, such as MRI machines.

Back
Top