Cdu 14: Doan mach dien xoay chieu khong phan nhanh gom a/^n day C O tir cam L , dien t r d thuan R va tu dien c6 dien dung C K h i dong dien c6 tan so' goc chay qua doan mach t h i he so cong suat cua doan mach A bang B phu thuoc dien trof thuan cua doan mach C b k n g l D phu thuoc tong irb cua doan mach GiSi K h i dong dien c6 tan so goc chay qua doan mach t h i xay hi^n tiTtfng cong hLfomg K h i u, i cung pha va he so cong suat cua doan mach bang Vdy chgn dap an C Cdu 15: Cho hai dao dong dieu hoa cung phiTcfng, cung tan so, cung bien va c6 cac pha ban dau la — va - — Pha ban dau cua dao dong tong hcfp hai dao dong tren bkng: A ^ 12 B ^ C D ^ Giai Pha ban dau cua dao d6ng tong hap hai dao dong tren bang 7t 12 Vdy chgn dap an A Cdu 16: Trong mot mach dao dong LC khon^ c6 dien t r d thuan, c6 dao dpng dien tii ttf (dao dong rieng) Hieu dien the CLTC dai gifla hai ban tu va ctr&ng dong dien ciJc dai qua mach Ian Itfcft la Uo va I Q T Tai thdi diem ctfofng dong dien mach c6 gia t r i y t h i 16n hieu dien the giiJa hai ban tu dien la: A ^ U o C.iu, B |Uo D ^ U , Gi^i Chi ti^t de thi T S B H , C D IVIon Vat If