Question

The current in a coil of self inductance $5H$ is increasing according to $i=2si{n}^{2}t$ . The amount of energy spent during the period when current changes from $0$ to $2$ amperes is:

• A. $10J$
• B. $5J$
• C. $100J$
• D. $2J$

Answer 1

Answer: (A)

$10J$

The energy stored in an inductance when current I is flowing through it is given by

$U=1/2\times L\times I^2$

Hence Energy spent = $1/2\times L\times (I_2^2-I_1^2)$

= $1/2\times 5\times (4-0)$

= $10J$