Electric Current in Moving Plate Capacitor with Velocity 6 m/s and U=600 V

[Noirro]

Homework Statement

Thin parallel plate capacitor is connected to a U=600 V current source. Find the electric current flowing in the circuit if one of the electrodes is pulled at v=6 m/s velocity. The electrodes are square (l=10 cm), the distance between them is d=1 mm.

Homework Equations

C=ε₀$\frac{A}{d+vt}$, C=$\frac{q}{U}$, I=$\frac{dq}{dt}$

The Attempt at a Solution

I tried finding the current by first expressing q from those capacitor equations and plugging it into the dq/dt equation, but there is still time t left. I am not sure if the answer depends on time or is it possible to find some constant value of I?

 

[ehild]

Homework Statement

Thin parallel plate capacitor is connected to a U=600 V current source. Find the electric current flowing in the circuit if one of the electrodes is pulled at v=6 m/s velocity. The electrodes are square (l=10 cm), the distance between them is d=1 mm.

Homework Equations

C=ε₀$\frac{A}{d+vt}$, C=$\frac{q}{U}$, I=$\frac{dq}{dt}$

The Attempt at a Solution

I tried finding the current by first expressing q from those capacitor equations and plugging it into the dq/dt equation, but there is still time t left. I am not sure if the answer depends on time or is it possible to find some constant value of I?

No, the current is not constant. Find the time dependence of the current, and the current at t=0.

ehild

 

[Noirro]

No, the current is not constant. Find the time dependence of the current, and the current at t=0.

ehild

OK thanks!

 

[CWatters]

Thin parallel plate capacitor is connected to a U=600 V current source

I assume you mean a voltage source.

 

[rude man]

Hint: i = C dV/dt is not the complete story.

The complete story is i = d/dt (CV).