An Ideal Solenoid Is 18

Short Answer

An ideal solenoid is 18.5 cm long,has a circular cross-section 2.20 cm in diameter,and contains 545 equally spaced thin windings.This solenoid is connected in a series circuit with an open switch,a 15.0-Ω resistor,and a battery of internal resistance 5.00 Ω and open-circuit terminal voltage of 25.0 V.(μ₀ = 4π × 10^-7 T • m/A)
(a)What is the maximum amount of energy that the solenoid will store after closing the switch?
(b)How long after closing the switch will it take for the stored energy in the solenoid to reach one-half of its maximum value?