Electric Potential Energy of a Cube of 8 protons

  • Thread starter acedeno
  • Start date
  • #1
36
2

Homework Statement



Suppose we there is a cube (a x a x a) made up of 8 protons. 1 at each point
What is the Electric Potential Energy


Homework Equations


U=q1*q1/4*pi*epsilon_0*r



The Attempt at a Solution


*U12 = Potential Energy to bring 2 to 1*
I'm aware of how to do the question but I'm not sure if I'm expressing it correctly. Remember that the potential energy is the work done configure this system in space.
W1=0
W2=U12
W3=U12+U13
W4=W3+U14
W5=W4+U15
W6=W5+U16
W7=W6+U17
W8=W7+U18

Then the Electric Potential Energy would be = Wtotal = W1+W2 . . . + W8

I am also aware that when I show my equation fully that some of the distances will be sqrt(2a^2)
 

Answers and Replies

  • #2
Redbelly98
Staff Emeritus
Science Advisor
Homework Helper
Insights Author
12,117
155

Homework Statement



Suppose we there is a cube (a x a x a) made up of 8 protons. 1 at each point
What is the Electric Potential Energy


Homework Equations


U=q1*q1/4*pi*epsilon_0*r



The Attempt at a Solution


*U12 = Potential Energy to bring 2 to 1*
I'm aware of how to do the question but I'm not sure if I'm expressing it correctly. Remember that the potential energy is the work done configure this system in space.
W1=0
W2=U12
W3=U12+U13
The work to bring in the 3rd charge is U13 + U23
W4=W3+U14
And for the 4th charge it's U14 + U24 + U34
W5=W4+U15
W6=W5+U16
W7=W6+U17
W8=W7+U18

Then the Electric Potential Energy would be = Wtotal = W1+W2 . . . + W8
Yes.
I am also aware that when I show my equation fully that some of the distances will be sqrt(2a^2)
 
  • #3
36
2
Thanks a lot! That really helps!
 
  • #4
SammyS
Staff Emeritus
Science Advisor
Homework Helper
Gold Member
11,331
1,012
Some pairs of protons have a separation distance of (√3)a .
 

Related Threads on Electric Potential Energy of a Cube of 8 protons

Replies
1
Views
6K
Replies
1
Views
4K
Replies
2
Views
3K
Replies
2
Views
10K
  • Last Post
Replies
1
Views
391
Replies
9
Views
891
Replies
8
Views
5K
  • Last Post
Replies
0
Views
2K
Replies
2
Views
9K
Replies
1
Views
6K
Top