Direction of a positive charge's velocity in an electric field.

In summary, The conversation covers questions related to electric potential, electric field, and capacitance. The link provided contains multiple choice questions and the conversation discusses the reasoning behind the answers. The conversation also touches on the definitions of electric potential and electric field, and their relationship. Additionally, there is a question about how the resistor affects the maximum charge stored in a capacitor. The hint given is to consider the voltage drop across the resistor when the capacitor is fully charged.
  • #1
theBEAST
364
0

Homework Statement


Here is the question with the answer:
http://dl.dropbox.com/u/64325990/phys153Q/21.5.PNG

The Attempt at a Solution


I initially thought it would be A but it isn't and does anyone know why?
 
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  • #2
hi theBEAST! :smile:
theBEAST said:
I initially thought it would be A but it isn't and does anyone know why?

wouldn't it only be A if the electric field was uniform? :wink:
 
  • #3
tiny-tim said:
hi theBEAST! :smile:


wouldn't it only be A if the electric field was uniform? :wink:

Ohhhh thanks that makes sense.

I have another one:
http://dl.dropbox.com/u/64325990/phys153Q/23.9.PNG

I thought this was A, if you put a point charge there... How could it feel a force?
 
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  • #4
what is the equation relating electric potential and electric field? :wink:
 
  • #5
tiny-tim said:
what is the equation relating electric potential and electric field? :wink:

Hmmmm one is 1/r and one is 1/r^2 so would this mean E ≠ 0? Thus F is not zero? Not really sure.
 
  • #6
you should know this definition :redface: …

the electric field is minus the gradient of the (scalar) potential …

E = -∇φ​

(what did you think the electric potential was for? :confused:)
 
  • #7
tiny-tim said:
you should know this definition :redface: …

the electric field is minus the gradient of the (scalar) potential …

E = -∇φ​

(what did you think the electric potential was for? :confused:)

Thanks Tim, I kind of know the definition... The concept was potential gradients was not taught in our physics class but I did read some of it on my own online. They are related in that the derivative of potential with respect to x is the electric field. So I am not sure how I can relate it to the multiple choice question :S.

I hope I'm not asking too many question at once but it is getting late and I would love to get a hint at what I am doing wrong for this question as well (once I wake up :P):
http://dl.dropbox.com/u/64325990/phys153Q/26.9.PNG

I thought R would affect the maximum charge stored as well because it affects the V of the battery and so the equation C=Q/V?
 
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  • #8
theBEAST said:
I thought R would affect the maximum charge stored as well because it affects the V of the battery and so the equation C=Q/V?

hint: when the capacitor C is fully charged, what is the voltage drop across the resistor R ? :wink:
 

FAQ: Direction of a positive charge's velocity in an electric field.

1. What is the direction of a positive charge's velocity in an electric field?

The direction of a positive charge's velocity in an electric field is determined by the direction of the electric field lines. The charge will accelerate in the direction of the electric field lines if the charge is positive.

2. How does the direction of an electric field affect the velocity of a positive charge?

The direction of an electric field determines the direction in which a positive charge will accelerate. The charge will accelerate in the direction of the electric field lines.

3. Can the direction of a positive charge's velocity in an electric field change?

Yes, the direction of a positive charge's velocity in an electric field can change if the direction of the electric field changes. The charge will always accelerate in the direction of the electric field lines.

4. What factors affect the direction of a positive charge's velocity in an electric field?

The direction of a positive charge's velocity in an electric field is primarily affected by the strength and direction of the electric field. Other factors such as the mass and charge of the particle can also play a role.

5. How can the direction of a positive charge's velocity in an electric field be determined experimentally?

The direction of a positive charge's velocity in an electric field can be determined experimentally by using a charged particle in an electric field and measuring its acceleration in different directions. Alternatively, the direction can also be calculated using mathematical equations that take into account the strength and direction of the electric field, as well as the properties of the charge and the particle.

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