Question

A parallel plate capacitor is connected to a DC battery supplying a constant DC voltage V₀= 1200V via a resistor R=1655kΩ. The battery has been connected for a long time. Each plate has an area A=182.5 m² . The left plate is at ground potential and the right plate is at positive potential. The separation between the capacitor plates is  D= 0.6m and all the points in the picture are far from the edges of the plates. The capacitor is placed on board of a space station where there is no gravity present.

In the coordinate system shown in the picture (x is a "horizontal" axis, y is "vertical" although names are purely conventional since there's no gravity), where all lengths are in meters, a positive charge q=9e-05C and mass m= 0.5g has been placed directly in point C(0.55,12) and let go. What is the speed, v, of that charge when it reaches point A(0.05,12)?

Which of the following graphs best represents the horizontal speed of your charge as function of time?

You decided to repeat the experiment, but this time you placed the same charge in point C before capacitor is charged, let go, and then connected the same power supply to the capacitor via the same resistor to charge it. Do not overcomplicated things: assume that the effect of any magnetic fields is negligible. Assuming that the axes scale on all graphs are the same what is the graph that best represents the horizontal speed of your charge as function of time in this experiment?

Answer 1