How Does Charge Distribution Affect Electrostatic Energy and Potential?

AI Thread Summary
The discussion revolves around calculating electrostatic energy and potential in systems with multiple charges and conducting spheres. The first problem involves four charges at the corners of a square, yielding an electrostatic energy of -4.7 J. The second problem compares the potentials of two conducting spheres, with the smaller sphere at 100V, while the potential of the larger sphere is debated among several options. The third problem involves three connected conducting spheres, where the charge on the large sphere in equilibrium is determined to be 2.0 x 10^-4 C. Participants express confusion over their calculations and the use of combinations in solving these electrostatic problems.
gwenle1
Messages
5
Reaction score
0
1. Four charges are placed at the corners of the square where the opp diagonals have +2microcoulombs and -2 coulombs. what is the electrostatic energy of the system? ANS: -4.7 J


2. Two conducting spheres that carry equal charges are very far from each other and from all other charges. One of these spheres has twice the radius of the other one. If the potential of the smaller sphere (relative to infinity) is 100V, the potential of the arger sphere (relative to infinity) is closest to... ANS: 100V, 200V, 50V, 25V, or 400V

3. three conducting spheres of radii 1m, 2m and 3m are connected by wires 50 meters long in a triangle with the angles 60 degrees each. a charge of 4x10^-4 C is initially placed on teh large sphere. determine the charge on teh large sphere in equilibrium. ANS 2.0 x 10^-4






The attempt at a solution
1) I tried using PE = kq1q1/R... found the sides and the diagonals but I got an answer of zero, which is wrong.

2) I found the net energy of both spheres, and then used this energy with the given potential to find the potential of the larger sphere, but i think I am rearranging wrong?

3) i drew a FBD diagram and did horizontal and vertical components on teh larger sphere, but I got a much larger number as my answer.

 
Physics news on Phys.org
You will have 4C2 combinations to consider.
Two of these will be diagonally opposite pairs and all others will be adjacent pairs.
 
I have no idea why you would use combinations for my problems
 
Was just telling you there would be 6 pairs to consider.
 
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Thread 'Correct statement about a reservoir with an outlet pipe'
The answer to this question is statements (ii) and (iv) are correct. (i) This is FALSE because the speed of water in the tap is greater than speed at the water surface (ii) I don't even understand this statement. What does the "seal" part have to do with water flowing out? Won't the water still flow out through the tap until the tank is empty whether the reservoir is sealed or not? (iii) In my opinion, this statement would be correct. Increasing the gravitational potential energy of the...
Back
Top