MCQ
Average energy stored in a pure inductance $L$ when a current $i$ flows through it, is
- A$L{i^2}$
- B$2L{i^2}$
- C$\frac{{L{i^2}}}{4}$
- ✓$\frac{{L{i^2}}}{2}$
✓
Answer
Correct option: D.
$\frac{{L{i^2}}}{2}$
d
(d) As we know $e = - \frac{{d\phi }}{{dt}} = - L\frac{{di}}{{dt}}$
(d) As we know $e = - \frac{{d\phi }}{{dt}} = - L\frac{{di}}{{dt}}$
Work done against back $e.m.f$. $e$ in time dt and current i is
$dW = - eidt = L\frac{{di}}{{dt}}idt = Li\;di$ $ \Rightarrow \;W = L\int_0^i {i\;di} = \frac{1}{2}L{i^2}$
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