A combination of two metal conductors of same shape,
placed close to each other, with one of the conductors being earthed
or grounded, is called a capacitor. A capacitor can store more charge
than either of the two conductors (from which it is made) taken
The amount of charge Q stored in a condenser (Capacitor)
is proportional to the P. d. V between the two conductors.
The constant 'C' is called the capacity (capacitance)
of the condenser.
In practice 1 mf, 1nf,
1 pf C 10-6, 10-9, (10-K Farad
capacities are used as 1 Farad Capacity condenser is of enormous
Parallel plate capacitor and its capacity
Two metal plates (rectangular) identical in all
respects and separated by distance 'd' is called parallel plate
Within the capacitor, the intensities of the electric
field due to a positive Q charge on the left plate and the induced
charge -Q on the right plate (which is grounded) are perpendicular
and within the same direction.
Since E is uniform (as d<< l, b, l
and b are lengths and breadths of plates) between the plates.