A capacitor can be used to produce a desired electric field. We consldered the parallel plate arrangement as a basic type of capacitor. Similarly, an inductor (symbol) con be used to near the middle of a long solenoid ) as our basic type fo inductor. if we establish a current i in the winding ( or turns ) of an inductro ( a solenoid ) the current produces a magnetic flux phi_(B) through the central region of the inductor. the inductance of the inductor is then [ L = (N phi_(E))/(i) ]( inductance defined ) where N is the number of turns. the windings of the inductor are said to the linked by the shared flux, and the product N phi_(E ) is called the magnetic flux linkage . the inductance L is thus a measure of flux produced by the inductor per unit of current . Now, consider a special type of inductor whose radius of turn R as shown in the adjacent figure and total number of turns is N. This special type of solenoid produces a magnetic field |vec(B)| = mu l r^(2) uniformly along the axis of the solenoid as shown in figure. r is the distance from the axis of solenoid. Value of self inductance of this inductor is given by