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www.GOALias.blogspot.comPhysicsCHAPTER 77.1 (a) 2.20 A(b) 484 W7.2 (a)300= 2121 . V2(b) 10 2 = 14. 1 A7.3 15.9 A7.4 2.49 A7.5 Zero in each case.7.6 125 s –1 ; 257.7 1.1 × 10 3 s –17.8 0.6 J, same at later times.7.9 2,000 W7.101 1ν =1, i.e., C =2 π LC2 24 π ν LFor L = 200 µH, ν = 1200 kHz, C = 87.9 pF.For L = 200 µH, ν = 800 kHz, C = 197.8 pF.The variable capacitor should have a range of about 88 pF to 198 pF.7.11 (a) 50 rad s –1(b) 40 Ω, 8.1 A(c) V Lrms= 1437. 5 V, V Crms= 1437. 5 V, V Rrms= 230 V1VLCrms= Irmsω0L− = 0Cω07.12 (a) 1.0 J. Yes, sum of the energies stored in L and C is conserved ifR = 0.3 −1(b) ω = 10 rads , ν = 159 Hz(c)q = q 0cos ω tT 3T(i) Energy stored is completely electrical at t = 0, , T, , .....2 2(ii) Energy stored is completely magnetic (i.e., electrical energyis zero) atT 3T 5Tt = , , ......., where4 4 41 T = = 6.3 ms .ν(d)AtT 3T 5TTt = , , ,....... , because q = q 0cos ω = q 0cos π = q 08 8 88 4 2 .302(e)2 ⎛2q 1 q ⎞Therefore, electrical energy = =0 which is half the total2C2⎜ ⎟⎝ 2C⎠energy.R damps out the LC oscillations eventually. The whole of theinitial energy (= 1.0 J) is eventually dissipated as heat.