Question

The current through a $6mH$ inductor is shown in the following graph. The induced $emf$ at $t=4ms$ will be :-

• A. ${10}^{3}V$
• B. $-23\times {10}^{3}V$
• C. $23\times {10}^{3}V$
• D. $zero$

Answer 1

The correct option is B $-23\times {10}^{3}V$

$\epsilon =L\frac{dI}{dt}$

$=-L\left(\frac{I_2-I_1}{t_2-t_1}\right)$

$=-4.6\times \left[\frac{0-5}{(6-5)\times {10}^{-3}}\right]$

$\epsilon =23kV$