2. The area of the plate of a flat air condenser is 0.01 m2, the distance between them is 2 cm. A potential difference of 3 kV is applied to the plates of the condenser. What will be the field strength of the capacitor if, without disconnecting it from the voltage source, the plates are pushed to a distance of 4 cm. Find the capacitor energy before and after the plates are pushed apart.

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