Question

An average induced emf of $0.20 V$ appears in a coil when the current in it is changed from $5 A$ in one direction to $5A $ in the opposite direction in $0.20$ sec. Find the self induction of the coil.

• A. $4 \times 10^{-3} H$
• B. $2 \times 10^{-3} H$
• C. $2 \sqrt{2} \times 10^{-3} H$
• D. $3 \sqrt{3} \times 10^{-1} H$

Answer 1

Answer: (A)

As we know,
$e=L \frac{d I}{d t} \Rightarrow 0.20$
$=\frac{L(5-(-5))}{0.20}$
$\frac{0.20 \times 0.20}{5+5}= L$
$\Rightarrow 4 \times 10^{-3} H$