- #1
AdityaDev
- 527
- 33
Homework Statement
A capacitor of capacity C is charged with potential difference V. Another capacitor of capacity 2C is charged to 4V.they are connected with reverse polarity after removing batteries. The heat produced during redistribution of charges is...
Homework Equations
##Q = CV##
##U = 0.5CV^2##
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The Attempt at a Solution
Let Q be charge in capacitor with capacitance C and other be q initially.
##Q=CV##
##q=8CV##
##U1 = Q^2/2C + q^2/(4C)##
##U2 = (Q+q)^2/2(C+4C)##
U2 is final energy... Net charge is Q+q and since potential difference becomes same when connected... C(net) = C1+C2
Heat = delta U
##delta U = C1C2(V1-V2)/(C1+C2)##
Here V gets added up...( I don't know why... But I got the answer)
Hence ##U = C1C2(V1+V2)/(C1+C2)##
You will get correct answer but why V1 + V2 is there some other method?