A parallel plate capacitor of capacitance 200 μF is connected to a battery of 200 V. A dielectric slab of dielectric constant K = 2 is now inserted into the space between the plates of the capacitor while the battery remains connected. The change in the electrostatic energy stored in the capacitor will be:

Two capacitors of 10 μF each are connected in series. This combination is connected in parallel with a 20 μF capacitor. The total capacitance is:

A gang condenser is formed by interlocking 9 parallel plates alternately. The distance between the consecutive plates is 0.885 cm and the overlapping area of consecutive plates is 5 cm2. The total capacity of the unit is (ε0 = 8.85 × 10-12 F/m):