Question

If emf induced in a coil is $2V$ by changing the current in it from $8A$ to $6A$ in $2\times {10}^{-3}s$, then the coefficient of self induction is

• A. $2\times {10}^{-3}H$
• B. ${10}^{-3}H$
• C. $0.5\times {10}^{-3}H$
• D. $4\times {10}^{-3}H$

Answer 1

Answer: (A)

$2\times {10}^{-3}H$

Given : $E=2$ V $\Delta t=2\times {10}^{-3}$ s

Change in current $\Delta I=6-8=-2$ A

Using $E=-L\frac{\Delta I}{\Delta t}$

$\therefore$ $2=-L\times \frac{-2}{2\times {10}^{-3}}$ $⟹L=2\times {10}^{-3}H$