Electric Force on a Charge in a Solenoid

In summary, the conversation discusses the direction of the induced EMF in relation to a changing magnetic flux and the force experienced by a positive charge. The key word "increasing" refers to the Faraday EMF and the changing magnetic flux. The EMF is the integral of an induced electric field and the positive charge experiences a force based on this electric field and its velocity in a magnetic field.
  • #1
Helly123
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Homework Statement


http://[url=https://ibb.co/dgUy6T]https://preview.ibb.co/iyqS0o/20180525_213806.jpg
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Since i only know the field direction, increasing go into page. Why the answer is C?

[ATTACH=full]226152[/ATTACH]
Why the answer "a" ?

The R and r on the pic is respected to what?

[h2]Homework Equations[/h2][h2]The Attempt at a Solution[/h2]
Right hand rule : finger tip = current
Thumbs = force
Palm = B

Or
Finger tip = velocity
Thumbs = current
Palm = B
 

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  • #2
The key word here in the statement of the problem is "increasing" and they should say "increasing with time". The question involves the Faraday EMF that occurs. The changing magnetic flux creates an EMF. They basically are asking the direction of the induced ## E ## of the EMF.
 
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  • #3
Could it be like this?
20180526_153723.jpg


20180526_153612.jpg


Force direction the same as Emf's ?
 

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  • #4
That is correct. The EMF is the integral of an induced electric field along the path. The electric field ## \vec{E}=\vec{E}_{induced} ## is what the positive charge responds to, and experiences a force ## \vec{F}=q(\vec{E}+\vec{v} \times \vec{B}) ##. ## \\ ## (And of course, when they say "placed at point b", etc. that means ## \vec{v}=0 ## so that ## \vec{v} \times \vec{B}=0 ## ).
 
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  • #5
Charles Link said:
That is correct. The EMF is the integral of an induced electric field along the path. The electric field ## \vec{E}=\vec{E}_{induced} ## is what the positive charge responds to, and experiences a force ## \vec{F}=q(\vec{E}+\vec{v} \times \vec{B}) ##. ## \\ ## (And of course, when they say "placed at point b", etc. that means ## \vec{v}=0 ## so that ## \vec{v} \times \vec{B}=0 ## ).
Thank you @Charles Link
 
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1. What is a solenoid?

A solenoid is a long, cylindrical coil of wire that is used to create a magnetic field when an electric current is passed through it.

2. How does an electric charge experience a force in a solenoid?

When an electric current flows through a solenoid, it creates a magnetic field. This magnetic field will exert a force on any electrically charged particles that pass through it, causing them to experience a force.

3. What factors affect the strength of the electric force on a charge in a solenoid?

The strength of the electric force on a charge in a solenoid depends on the strength of the electric current flowing through the solenoid, the distance between the charge and the solenoid, and the direction of the magnetic field created by the solenoid.

4. How is the direction of the electric force on a charge in a solenoid determined?

The direction of the electric force on a charge in a solenoid is determined by the direction of the magnetic field created by the solenoid. The force will always be perpendicular to both the direction of the magnetic field and the direction of the charge's motion.

5. Can the electric force on a charge in a solenoid be controlled?

Yes, the electric force on a charge in a solenoid can be controlled by changing the strength of the electric current flowing through the solenoid or by changing the distance between the charge and the solenoid. The direction of the force can also be controlled by changing the direction of the magnetic field created by the solenoid.

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