The mutual inductance between a primary and secondary circuit is `0.5H`. The resistance of the primary and the secondary circuits are `20 ohms` and `5ohms` respectvely. To genrate a current of `0.4A` in the secondary,current in the primary must be changed at the rate of

Options

A. 4.0 A/s
B. 16.0 A/s
C. 1.6 A/s
D. 8.0 A/s

Answer

A

Explanation

`M=0.5H,R_(P)=20Omega,R_(S)=5Omega`
`e_(2)=M(di_(1))/dtrArri_(2)R_(2)=M(di_(1))/dtrArr(di_(1))/dt=(0.4xx5)/0.5`
`rArr(di_(1))/dt=4A//sec`.