Question

For a current carrying inductor, emf associated is 20mV. Now, current through it changes from 6A to 2A in 2s. The coefficient of mutual inductance is

• A. 20mH
• B. 10mH
• C. 1mH
• D. 2mH

Hint:

The emf induced in an inductor is proportional to the rate of change of current through it and the mutual inductance between inductors.

Answer 1

The Correct Option is B

Step 1: Formula for Mutual Inductance.
The formula for emf induced due to a changing current in an inductor is: \[ \text{emf} = - M \frac{\Delta I}{\Delta t} \] where \( M \) is the mutual inductance, \( \Delta I \) is the change in current, and \( \Delta t \) is the time interval.
Step 2: Substituting the Given Values.
Substituting the given values: \[ 20 \times 10^{-3} = - M \frac{(6 - 2)}{2} \] Solving for \( M \), we get \( M = 10 \, \text{mH} \). Step 3: Conclusion.
The correct answer is (B), 10mH.