Verified Solution • 2025–26 Session moderate

QJEEAdv17Phafbf: JEE Advanced 2017 Physics - Class 12 JEEAdv17Phafbf Solution: In Process 2, total energy dissipated across the resistance E D …

In Process 2, total energy dissipated across the resistance ED is

Multiple Choice Options

  • A ED=13(12CV02){E_D} = {1 \over 3}\left( {{1 \over 2}CV_0^2} \right)
  • B ED=3(12CV02){E_D} = 3\left( {{1 \over 2}CV_0^2} \right)
  • C ED=3CV02{E_D} = 3CV_0^2
  • D ED=12CV02{E_D} = {1 \over 2}CV_0^2

Step-by-Step Verified Solution

Process 1 :

Voltage is set to V0/3

Charge supplied = CV03{{C{V_0}} \over 3}

Energy supplied = V03×CV03=CV029{{{V_0}} \over 3} \times {{C{V_0}} \over 3} = {{CV_0^2} \over 9}

Process 2 :

Voltage is raised to 2V0/3

additional charge supplied = 2V0C3−V0C3=CV03{{2{V_0}C} \over 3} - {{{V_0}C} \over 3} = {{C{V_0}} \over 3}

Energy supplied = 2V03×CV03=2CV029{{2{V_0}} \over 3} \times {{C{V_0}} \over 3} = {{2CV_0^2} \over 9}

Process 3 :

Voltage is raised to V0

additional charge supplied = V0C−2V0C3=CV03{V_0}C - {{2{V_0}C} \over 3} = {{C{V_0}} \over 3}

Energy supplied = V0×CV03=CV023{V_0} \times {{C{V_0}} \over 3} = {{CV_0^2} \over 3}

Total energy supplied to circuit = CV029+2CV029+CV023{{CV_0^2} \over 9} + {{2CV_0^2} \over 9} + {{CV_0^2} \over 3}

=69CV02=23CV02= {6 \over 9}CV_0^2 = {2 \over 3}CV_0^2

Final energy stored in capacitor = 12CV02{1 \over 2}CV_0^2

Therefore,

Energy dissipated ED = Energy supplied −- Energy stored

=23CV02−12CV02= {2 \over 3}CV_0^2 - {1 \over 2}CV_0^2

=4CV02−3CV026=16CV02= {{4CV_0^2 - 3CV_0^2} \over 6} = {1 \over 6}CV_0^2

=13(12CV02)= {1 \over 3}\left( {{1 \over 2}CV_0^2} \right)

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