28-40MODELS OF ELECTRIC CIRCUITS Using the Laplace transform and showing the details, findthe current ) in the circuit in Fig. 126, assuming K0) = 0and: 28. R= 1 kn (=1000

2), L I H, v = 0 if 0 T 30. R 10 N, L 0.5 H, u 200t V if 0 2 31. Discharge in RC-circuit. Using the Laplace transform,find the charge q1) on the capacitor of capacitance Cin Fig. 127 if the capacitor is charged so that its potentialis 6 and the switch is closed at t = 0. \begin{array}{l} R=25 \Omega, L=0.1 \mathrm{H}, v=490 \mathrm{e}^{-3 t} \mathrm{~V} \text { if } 01 \end{array}