Question

A coil of resistance $20\Omega$ and inductance $5H$ has been connected to a $100V$ battery The energy stored in the coil after a long time is

• A. $31.25J$
• B. $62.5J$
• C. $125J$
• D. $250J$

Answer 1

The correct option is B $62.5J$



Energy stored in an inductor is given by
$E=\frac{1}{2}L{I}^2$

Current at steady state $=\frac{V}{R}=\frac{100}{20}=5A$

$\therefore E=\frac{1}{2}\left(5\right)(5{)}^2=\frac{125}{2}=62.5J$