Force on a particle in a homogeneous electric field

  • Thread starter Arcthor
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  • #1
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I understand that in a homogeneous electric field, the force on a particle, regardless of its location, is the same.

How can this be? Wouldn't a positively charged particle experience a greater force when near the positively charged side? What am I missing?
 

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  • #2
Quantum Defect
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I understand that in a homogeneous electric field, the force on a particle, regardless of its location, is the same.

How can this be? Wouldn't a positively charged particle experience a greater force when near the positively charged side? What am I missing?
Don't think about how the field was created, just imagine the field being in some box that defines the region over which the field is uniform (i.e. there is nothing but the field there, and the particle). If the region is really, really big, there are no real landmarks (wiggliness of the field, etc.) the only thing that you can see is the strength of the field by the force on the charge. If the field strength is the same everywhere, should the force felt be any different?

Think of the analogy with the force due to gravity for a ball placed on an incline. Is the force on a ball bigger at the top of the incline or at the bottom of the incline?
The thing that is different is the gravitaional potential. When the ball is at the top of the incline, the gravitational potential is larger (there is the ability to extract more work from its falling). Same goes for a charge in a uniform electric field: force is the same, but the potential is different.
 
  • #3
A.T.
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I understand that in a homogeneous electric field, the force on a particle, regardless of its location, is the same.

How can this be?
Per definition.
 
  • #4
34
1
Don't think about how the field was created, just imagine the field being in some box that defines the region over which the field is uniform (i.e. there is nothing but the field there, and the particle). If the region is really, really big, there are no real landmarks (wiggliness of the field, etc.) the only thing that you can see is the strength of the field by the force on the charge. If the field strength is the same everywhere, should the force felt be any different?

Think of the analogy with the force due to gravity for a ball placed on an incline. Is the force on a ball bigger at the top of the incline or at the bottom of the incline?
The thing that is different is the gravitaional potential. When the ball is at the top of the incline, the gravitational potential is larger (there is the ability to extract more work from its falling). Same goes for a charge in a uniform electric field: force is the same, but the potential is different.
Thank you! I makes complete sense now :) Sorry for late reply, was busy studying for the test lol
 

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