## H C VERMA PHYSICS BOOK SOLUTIONS CAPACITORS PART-1

Solved Examples
Example 31.1
A capacitor gets a charge of 60 muC when it is connected to a battery of emf 12 V. Calculate the capacitance of the capacitor.
Sol.
The potential difference between the plates is the same as the emf of the battery which is 12 V. Thus, the capacitance is

Example 31.3
Calculate the capacitance of a parallel–plate capacitor having 20 cm × 20 cm square plates separated by a distance of 1.0 mm.
Sol.
The capacitance is

Example 31.4
Calculate the charge on each capacitor shown in figure .

In series combination, each capacitor has equal charge and this charge equals the charge suppled by the battery. Thus, each capacitor has a charge of 200 muC.

Example 31.5    Find the equivalent capacitance of the combination shown in figure between the points P and N.

Example 31.6    Find the equivalent capacitance of the combination shown in the figure between the points P and N.

Sol.    Let us connect a battery between the points P and N. The charges and the potentials are shown in figure.The positive terminal of the battery supplies a charge +Q which appears on the plate A 1 . The facing plate A 2 gets a charge – Q. The plates A 2 , A 3 and A 5  taken together form an isolated system. The total charge on these three plates should be zero. Let a charge Q 1 appear on A 3 , then a charge Q – Q 1  will appear on A 5 to make the total charge zero on the three plates. The plate A 4 will get a charge – Q 1 (facing plate of A 3 ) and A 0  will get a charge – ( Q–Q 1 ) (facing plate of A