- #1
cupid.callin
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- 1
The question is like this:
8 charges of magnitude q and different sighs are placed at corners of a cube of side a.
Find the work done in taking them far away from each other.
U = kq1q2/r
W = ΔU
First i found out the potential energy of a +q charge
U = -3kq2/a + 3kq2/√2a - Kq2/√3a
and the same comes out to be for -q charge (of course)
So for 1 charge,
W = Uf - Ui
W = 0 - ( -3kq2/a + 3kq2/√2a - Kq2/√3a )
W = 3kq2/a - 3kq2/√2a + Kq2/√3a
So work done for 8 charges = 8W ... Right?
But its wrong.
Some help please.
8 charges of magnitude q and different sighs are placed at corners of a cube of side a.
Find the work done in taking them far away from each other.
Homework Equations
U = kq1q2/r
W = ΔU
The Attempt at a Solution
First i found out the potential energy of a +q charge
U = -3kq2/a + 3kq2/√2a - Kq2/√3a
and the same comes out to be for -q charge (of course)
So for 1 charge,
W = Uf - Ui
W = 0 - ( -3kq2/a + 3kq2/√2a - Kq2/√3a )
W = 3kq2/a - 3kq2/√2a + Kq2/√3a
So work done for 8 charges = 8W ... Right?
But its wrong.
Some help please.