Problem on distribution of charges between charged/uncharged spheres

AI Thread Summary
Two spherical conductors, B and C, initially carrying equal charges repel each other with force F. When an uncharged conductor A contacts B, charges redistribute, leaving B with Q/2 and A with Q/2. Next, A contacts C, leading to an equal distribution of the total charge (3Q/2) between A and C. Consequently, after both contacts, B retains Q/2, while A and C each have 3Q/4. The new force of repulsion between B and C is calculated to be 3F/8.
frostchaos123
Messages
16
Reaction score
0

Homework Statement



2 Spherical conductors B and C having equal radii and carrying equal charges repel each other with force F. Another conductor A having same radius as B but uncharged is brought into contact with B, and then C and then removed from both.

Find the new force of repulsion between B and C. (Answer should be 3F/8)


Homework Equations



Coulomb's law


The Attempt at a Solution



Since when an uncharged sphere A contacts with B, the charges from B flow over, leaving B with half of the charges, and A with half of the charges (initial assumption).

Afterwards charged A contacts C, but i am not quite sure about the distribution of charges from here on. Since now A have half of the original charges, does it mean that 1/4 of the charges of C will flow into A to equalise?

Or is my initial assumption that A will get half of the charges from B wrong in the first place?

Any help is much appreciated.
 
Physics news on Phys.org
I think the charge is going to equalise. So you can just add the charge of A and C and divide it by 2 to get the total charge on each one.

So, let's say A has 0 and B and C have Q.
A touches B so they both have Q/2.
A touches C. The charge distributes equally. So, total charge is 3Q/2. So, there will be 3Q/4 on each one.
So, you're right.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
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 'Trying to understand the logic behind adding vectors with an angle between them'
My initial calculation was to subtract V1 from V2 to show that from the perspective of the second aircraft the first one is -300km/h. So i checked with ChatGPT and it said I cant just subtract them because I have an angle between them. So I dont understand the reasoning of it. Like why should a velocity be dependent on an angle? I was thinking about how it would look like if the planes where parallel to each other, and then how it look like if one is turning away and I dont see it. Since...
Back
Top