Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

I have the following setup:

A <---- wire ----> B

$V_b - V_a = \Delta v = \text{a positive value}$

I have two questions:

  1. Which end of the wire has a higher potential?
  2. What is the direction of the electric field inside the wire?
share|improve this question
add comment

2 Answers 2

up vote 3 down vote accepted

From the given information that $V_b-V_a$ is positive, we know that $V_b>V_a$. The word "potential" means simply $V$, so point B is at a higher potential than point A.

Once you know that, you can go and remind yourself of the relationship between electric field and potential (no doubt it's in your textbook). That'll give you the answer to your second question.

share|improve this answer
    
You dont understand beginners problems. And High or low is simply wron. -1 –  Georg Feb 22 '11 at 15:26
    
+1 You are totally right. –  user1355 Feb 22 '11 at 15:44
    
I have no idea what @Georg means. This is totally right. –  kharybdis Feb 22 '11 at 18:03
add comment

Obviously $V_b$ is at a higher potential as Ted already answered. The relation between field and potential is simple.

$\vec E = - \vec \nabla V$ In this one dimensional case it is $\vec E = - \frac {dV}{dx} \hat x $ where $\hat x$ is the unit vector along the positive x direction. So you see the field is in the $- x$ direction i.e. along $\vec {BA}$

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.