Question

A parallel plate capacitor is connected to a battery. The plates are pulled apart with a uniform speed. If x is the separation between the plates, the time rate of change of electrostatic energy of capacitor is proportional to–

• A. x^–2
• B. x
• C. x^–1
• D. x²

Answer 1

Answer: (A)

x^–2

Answer 2

U =$\frac { 1 } { 2 }$CV₀² = $\frac { 1 } { 2 }$ V₀²

$\frac { \mathrm { dU } } { \mathrm { dt } }$ = – $\frac { \mathrm { V } _ { 0 } ^ { 2 } \varepsilon _ { 0 } \mathrm {~A} } { 2 }$ = –