Question

A coil of resistance $10\Omega$ and an inductance 5 H is connected to a 100 V battery. The energy stored in the coil is

• A. 125 erg
• B. 125 J
• C. 250 erg
• D. 250 J

Answer 1

Answer: (D)

250 J

Steady state current
$I_0=\frac{V}{R}=\frac{100}{10}=10A$
$\therefore$ Energy stored in the coil $U=\frac{1}{2}L{I}_0^2$
$=\frac{1}{2}\times 5\times {\left(10\right)}^2=250J$