Solve Electrical Work Problem: 15V to 5V

  • Thread starter Thread starter punjabi_monster
  • Start date Start date
  • Tags Tags
    Electrical Work
AI Thread Summary
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
Messages
60
Reaction score
0
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
 
Physics news on Phys.org
What is the system in question?
 
its an hypothetical electrochemical cell.
 
Geometry? Edge length of 1 cm can be appliead to anything.
 

Thread 'Prove that evolution is constant (Provide at least two arguments to support your position)'

I don't get how to argue it. i can prove: evolution is the ability to adapt, whether it's progression or regression from some point of view, so if evolution is not constant then animal generations couldn`t stay alive for a big amount of time because when climate is changing this generations die. but they dont. so evolution is constant. but its not an argument, right? how to fing arguments when i only prove it.. analytically, i guess it called that (this is indirectly related to biology, im...
View full post »
Thread 'How to find the pH of a galvanic cell (MIT OCW problem set)'

Thread 'How to find the pH of a galvanic cell (MIT OCW problem set)'

This is the final problem in this problem set from MIT OCW. Here is what I did to try to solve it The table cited in the problem is below We can easily spot the two redox couples that are in the electrochemical cell we are given. The hydrogen-based electrode has standard potential zero, and the silver-based electrode has standard potential 0.22. Thus, the hydrogen electrode, with the lower potential, is the reducing agent (ie, it is where oxidation happens) and is the anode. Electrons...
View full post »

Similar threads

If a charged particle is released from rest....
Replies
5
Views
4K
What is the radius of the orbit of an electron?
Replies
2
Views
2K
How to find the magnitude of the electric field?
Replies
13
Views
5K
Electric Field and a Charged Cork Ball on a Massless String
Replies
1
Views
7K
Difference between Electric Potential energy and Potential energy
Replies
3
Views
4K
Is the Chosen 5V Power Supply Justified for This Instrumentation Op-Amp Problem?
Replies
1
Views
2K
Can E=V/d be used to calculate the electric field of a dipole?
Replies
1
Views
2K
Point charge on a string in an electric field
Replies
6
Views
5K
Find the electric field between 2 finite discs
Replies
16
Views
1K
Finding Dimensions of plates in Electric Field
Replies
29
Views
2K

Hot Threads

Recent Insights

Back
Top