Heat evolved.

What amount of heat will be generated in the circuit shown after the switch Sw is shifted from position 1 to position 2?

21 Answers

66
kaymant ·

@kamalendu, with your correction taken into account and with a sign correction (in the last line in post #3, there should be a plus in front CE2), your solution is correct. The heat evolved turns out to be \dfrac{1}{2}C\mathcal{E}_2^2. Intersetingly, this heat generated does not depend on \mathcal{E}_1!!

1
kamalendu ghosh ·

yes!!

21
tapanmast Vora ·

oh okay,

W = QV!!!

1
kamalendu ghosh ·

THIS IS WORK DONE BY BATTERY.....W=E1*CE2

21
tapanmast Vora ·

FRM WER does this cum : Ce1e2

1
kamalendu ghosh ·

final eqn,

0.5(e2-e1)2+Ce1e2-0.5ce12

21
tapanmast Vora ·

if u knoe pl. reply kamlengdu

21
tapanmast Vora ·

arre but if the ans is 0.5CE22 then kahi na kahi to katega hi naa.....

can u pl. write the Final Equation

1
kamalendu ghosh ·

@tapan..it does get cancelled.....DO IT CAREFULLY

21
tapanmast Vora ·

UI = 0.5C(E1-E2)2

UF = 0.5C E12

wer did CE1E2 term get cancelled?????///

1
kamalendu ghosh ·

REALLY ...I WAS VERY CASUAL IN SOLVING IT...BASH ME!! SO MANY SILLY ERRORS!!

1
kamalendu ghosh ·

hmm...

1
kamalendu ghosh ·

check my posts am i right??

66
kaymant ·

thats not correct sky

1
skygirl ·

no comments ? am i right or wrong ?

1
skygirl ·

initially wen switch 1 was closed,

charge in the capacitor = q1 = (ε1 - ε2)C

then, when switch 2 is closed,

charge in the capacitor = q2 = - Cε1

net charge flowing through ε1 = C(ε2 - 2ε1)

energy supplied by ε1 = heat produced in the circuit

= Cε1(ε2 - 2ε1)

1
kamalendu ghosh ·

ooops!! another mistake....sorry..W=CE1E2....Now I think I am right

66
kaymant ·

Work done by battery is CE2?? That is dimensionally wrong.

1
kamalendu ghosh ·

am i right??sir??

1
kamalendu ghosh ·

theres a mistake in my post Uf=0.5CE12
not 0.5CE22

1
kamalendu ghosh ·

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