In the figure is shown two charges, Q1 and Q2. Around each charge is a circle, t

Question

In the figure is shown two charges, Q1 and Q2. Around each charge is a circle, the circles having the same radius. So, each point on the circles is the same distance from one of the charges. For this problem, let Q2 > 0 and Q1 = - Q2. (Warning! This may change if you do this question twice!) Consider moving a negatively charge object, at a constant speed, along each of the four paths shown and labeled A, B, C, and D. The paths start at one of the two black dots and end at the arrow heads on the path. (So, for example, moving the negative charge along the path A means the charge starts at the dot on the right circle and ends up at the bottom of the left circle.) Below are rankings of these paths. Which one of thes rankings correctly lists these paths in order of the change in potential energy of the negative charge as it is moved along the path? In other words, the "highest" for "first" path should have the largest change in potential energy. As always, the change is final (arrow head) minus initial (dot), negative numbers are less than positive numbers, and more negative numbers are less than less negative numbers. Question 1 options: 1) C > B > D > A 2) B = C > A = D 3) C > D > A > B 4) A = D > B = C 5) D > C > B > A 6) B > C > A > D 7) A > D > B > C 8) C = D > A = B 9) A > B > C > D 10) D > A > C > B 11) B > A > D > C 12) A = B > C = D 13) A = B = C = D

Explanation / Answer

The answer is (12) A = B > C = D

Explanation:

As per the question Q1 is negative and Q2 is positive. Let the moving negative charge be Q3.

When a negative Q3 starts at the dot at Q2, which is positively charged, there will be a net force of attraction between Q2 and Q3 and more work will be required to seperate them out and getting it closer to the other negative charge Q1, as the force between Q1 and Q3 will be that of repulsion.

Now when Q3 starts at the dot at Q1, there is already a force of repulsion between Q1 and Q3 which will tend to push Q3 aqay from Q1 and Q2 tends to attract Q3 towards itself, so the net work done for bringing Q3 from Q1 to Q2 will be lesser than getting it from Q2 to Q1.

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.