Question

Here is the same constant field from Problem 2.1, but this time there are no charges visiting this field. Two equipotential lines are illustrated, at the x-coordinates indicated on the diagram. Calculate the difference in potential, |Delta V|, between the two equipotential lines. (Absolute value, please.) Now suppose that a charged particle moves from the left equipotential to the right equipotential (like in problem 2.1.) What is the Delta V that the charged particle experiences if it is a POSITIVE particle? (No absolute value now, tell me whether Delta V is positive or negative.) What is the Delta V that the charged particle experiences if it is a POSITIVE particle? (No absolute value now, tell me whether Delta V is positive or negative.)

Answer 1

i) When positive charged particle moves from left to right equipotential surface, then the field does positive work on it and potential energy decreases.

$V=\frac{W}{q}$

Thus, Potential difference will be positive.

ii) When negative charged particle moves from left to right equipotential surface, then the field does negative work on it and potential energy increases.

$V=\frac{W}{q}$

Thus, Potential difference will be positive.