1. A flat air condenser, the distance between the plates of which is 2 cm, is charged up to a potential difference of 3000 V. What will be the field strength of the capacitor if, without disconnecting it from the voltage source, the plates are extended to a distance of 5 cm? Calculate the energy of the capacitor before and after the separation of the plates. The area of each plate is 100 cm2.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)