The relay of Fig. 3.6 is modified in such a fashion that the air gaps surrounding the plunger are no longer uniform. The top air-gap length is increased to gtop = 3.5 mm and that of the bottom gap is increased to gbot = 2.5 mm. The number of turns is increased to N = 1500. Calculate the stored energy as a function of plunger position (0 < x < d) for a current of i = 5 A. Figure 3.6 (a) Relay with movable plunger for Example 3.2. (b) Detail showing air-gap configuration with the plunger partially removed. + Magnetic plunger Magnetic flux Lossless N-turn coil Magnetic core H- 00 (a) (b)