For two coils inductively coupled, the mutual inductance is 1.9 H. The current through primary changes by 6 A in 1 ms. The induced e.m.f. is

11.4 mV       11.4 V  11.4 kV 1.14V

11.4 kV

$ \xi = M\frac{\Delta I}{\Delta t}= 1.9\times \frac{6}{10^{-3}} = 11.4KV$