476 



THE ELECTROMAGNETIC FIELD. [PT. III. CH. XII. 



inflexion, but rises continuously, the appearance of its represen- 

 tative curve to the eye being the same as in the case of a single 

 circuit. The growth of the currents is represented in Fig. 92. 



FIG. 92. 

 The total quantity flowing in the secondary is 



(i 3 ) I""/,*- 



Jo 



EM 



EM 



This result may also be obtained by direct integration of the 

 second of equations (4), with E 2 = 0, 



M(I^-I^ 

 (14) 



To find the effect of breaking the primary current, we have 

 /! (0) = E/Rj., / x (1) = 0, so that the whole quantity passing in the 

 secondary on breaking is the same as on making. This is one of 

 Faraday's fundamental results. The manner of variation of the 

 secondary is, on the contrary, very different from that on making. 

 After the break we have to consider the primary circuit as sup- 

 pressed, so that the secondary is to be considered by itself, and 

 varies according to equation (3) above, where I lf the final value, is 

 zero, and 7 , the initial value, is to be found from the above value 

 of the time-integral of the secondary, 



. _R2 t 



6 2 dt - 



J 



EM 



