In Fig. 30.11, switch S1 is closed while switch S2 is kept open. The inductance is L = 0...

In Fig. 30.11, switch S1 is closed while switch S₂ is kept open. The inductance is L = 0.115 H, and the resistance is R = 120 Ω. (a) When the current has reached its final value, the energy stored in the inductor is 0.260 J. What is the emf E of the battery? (b) After the current has reached its final value, S₁ is opened and S₂ is closed. How much time does it take for the energy stored in the inductor to decrease to 0.130 J, half of the original value?