Question

If an emf of $25V$ is induced when the current in the coil changes at the rate of $100A{s}^{-1}$, then the coefficient of self induction of the coil is

• A. $0.3H$
• B. $0.25H$
• C. $2.5H$
• D. $0.25mH$

Answer 1

Answer: (B)

$0.25H$

Rate of change of current, $\frac{di}{dt}=100$ $A{s}^{-1}$

Magnitude of emf induced in the coil, $|E|=25$ V

Using: $|E|=L\frac{di}{dt}$ where $L$ is the coefficient of self inductance

$⟹$ $25=L\times 100$

$⟹$ $L=0.25$ $H$