Solve Electrical Work Problem: 15V to 5V

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    Electrical Work
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The discussion revolves around calculating the work done on a system when its voltage drops from 15V to 5V, specifically in a hypothetical electrochemical cell. The user initially calculated the work as -6.954 * 10^-11 J, which differs from a friend's result of 1.4 * 10^-7. Key equations used include the electric potential and charge relations, factoring in the permittivity of water. The edge length of the system is noted as 1 cm, but its application remains broad. Clarification on the system's specifics and geometry is sought to resolve the discrepancy in calculations.
punjabi_monster
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Hi there. I was attempting this problem but my answer is not agreeing with my friends.
He got 1.4 *10^-7
Any help will be appreciated.

Homework Statement


Calculate the work done on a system if its voltage drops from 15 V to 5 V.
edge length= 1 cm
water permittivity e=78.54e


Homework Equations



dwelec = (elec pot.)dQ
Q=(elec pot)2ed
e=78.54 * eo

The Attempt at a Solution


w = (elec pot.)f (Qf - Qi)
=(elec pot.)f (2ed)[(elec pot.)f - (elec pot.)i]
=(5V)(2(78.54)(8.854*10^-12)(0.001)(5V-15V)
= -6.954 * 10^-11 J
 
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What is the system in question?
 
its an hypothetical electrochemical cell.
 
Geometry? Edge length of 1 cm can be appliead to anything.
 

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