Question

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

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

Answer 1

Answer: (A)

4.0 A/s

Answer 2

By using $\left| e _ { 2 } \right| = M \frac { d i _ { 1 } } { d t }$ $i _ { 2 } = \frac { e _ { 2 } } { R _ { 2 } } = \frac { M } { R _ { 2 } } \frac { d i _ { 1 } } { d t }$ ⇒

$0.4 = \frac { 0.5 } { 5 } \times \frac { d i _ { 1 } } { d t }$ ;