Two capacitors C1 and C2 are charged to 120V and 200V respectively. It is found that by connecting them together the potential on each one can be made zero. Then what is the relation between C1 and C2 ?

Question

Two capacitors C1 and C2 are charged to 120V and 200V respectively. It is found that by connecting them together the potential  on each one can be made zero. Then what is the relation between C1 and C2 ?

priyar · Answer

@samigupta8

priyar · Answer

how can the potential on each be zero??

priyar · Answer

@ganeshie8 @Michele_Laino @Vincent-Lyon.Fr @IrishBoy123 @mayankdevnani

samigupta8 · Answer

After connection the charge will flow till they both reach a common potential..
And that can be 0(one case)..
So just do this q1+q2=q1f+q2f .
U will get the relation between C1 and C2

samigupta8 · Answer

Q1f n Q2f are 0 
 Since the final potential is 0..

priyar · Answer

@samigupta8.. ya so  C1(120V) + C2 ( 200V) = 0 right?

priyar · Answer

and, can coservaton of charges be done regardless of their config? (series/parallel)

priyar · Answer

*conservation

samigupta8 · Answer

The conservation of charge is always ensured!!!

priyar · Answer

oh okay ! thanks!!

priyar · Answer

and is the abv. relation correct? coz that isn't the answer..

samigupta8 · Answer

Do u wanna say that 3C1=5C2 is wrong relation??

priyar · Answer

how did you get this relation?
i got 3C1+5C2 = 0.. @samigupta8

priyar · Answer

@ganeshie8

ganeshie8 · Answer

V = Q/C

Would you agree that the excess charge on the plates has to be 0 for the voltage across the capacitor to be 0 ?

priyar · Answer

what do you mean by "excess charge"?

ganeshie8 · Answer

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ganeshie8 · Answer

How do you want to connect those two capacitors so that the excess charge on every plate becomes 0 ?

ganeshie8 · Answer

excess charge is the extra charge on the plates

It is the Q in the equation Q = CV

priyar · Answer

i thought it was charge on the capacitor..

priyar · Answer

what is the difference between "charge on the capacitor" and "excess charge on the capacitor"?

ganeshie8 · Answer

let me ask you a question

priyar · Answer

ok..

ganeshie8 · Answer

Suppose the capacitor plates are made up of Copper.

ganeshie8 · Answer

Whats the atomic number of copper ?

ganeshie8 · Answer

how many electrons/protons are there in one copper atom ?

priyar · Answer

29.. i know what is meant by atomic no. ..!

ganeshie8 · Answer

Capacitor plates are made up of metals like Copper.

These metals contain lattice structures pulled together by chemical bonds between atoms/molecules. Each atom contains 29 protons and electrons. 
So a capacitor plate is full of charge.

priyar · Answer

oh i think i got you point!!

priyar · Answer

*your

ganeshie8 · Answer

"charging a capacitor" refers to driving some of the existing charge from one plate to another. 

This creates excess charge on both the plates

priyar · Answer

excess charge is the charge that came from the battery right?

ganeshie8 · Answer

Nope. Battery is like a water pump. 

Does water come from a pump ?

priyar · Answer

no..ok..

ganeshie8 · Answer

Battery takes some electrons from one plate of the capacitor and puts them on the other plate

priyar · Answer

battery just provides a potential di.. to enable electron flow.. they electron are the free electrons of the conductor.. i asked if these where the excess charge

priyar · Answer

*diff.

priyar · Answer

* these

ganeshie8 · Answer

yes, you have correct understanding... im just making sure :)

ganeshie8 · Answer

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priyar · Answer

ok.. thank you!

ganeshie8 · Answer

so how do you want to connect those capacitors so that there wont be any excess charge on the plates ?

priyar · Answer

i am not sure..series?

ganeshie8 · Answer

make the connection and show me

priyar · Answer

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ganeshie8 · Answer

do you mean like this : 

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