Question

A coil of resistance 10 Ω and an inductance 5H is connected to a 100 volt battery. Then energy stored in the coil is

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

Answer 1

Answer: (D)

250 J

Answer 2

$U = \frac{1}{2}Li^{2} \Rightarrow U = \frac{1}{2} \times 5 \times \left( \frac{100}{10} \right)^{2} = 250J$