For the value of obtained in the above question, the time taken for 95% of the stored energy to be dissipated is close to
(a) 0.10 s (b) 0.15 s
(c) 0.50 s (d) 1.0 s
E_1 is the stored energy and E_2 is the dissipated energy. So,
\frac{i_2^2}{i_1^2}=\frac{E_2}{E_1}=0.95
Therefore, i_2^2=0.95 i_1^2 \Rightarrow i_2=0.9746 i_1
When the switch is in position 2,
i(t)=i_1 e^{-(R / L) t}=2 e^{-(60 / 10) t}=2 e^{-6 t} (i)
After 95% of energy dissipation,
i(t) = 2 – 2 × 0.97 = 0.05 A (ii)
Substituting Eq. (ii) in Eq. (i), we get
0.05=2 e^{-6 t} \Rightarrow t=0.5 s