Tru'd.ne THPT chuven KHTN dd thi thfr Dai hoc lan II BQ GrAO DUC VA EAO TAO TRUdNG THPT CHUYTN KHTN ffi, - nEm hoc 2012 - 2013 Me 313 Tranql /4 nd rHr THUDAI Hgc LAN II NAM Hec 20tz - 2013 tvt0N THI : vAr lf Thdi gian ldm bdi : 90 phitt Mdi cdu c6 04 phuong tin trd ldi, Thi sinh chon mQt 0I phtong dn trd ldi hqp $ nhdt Ma di:313 C0u L: Phit bi€u ndo sau ddy ld sai n6i v6 sbng cliQn ttr? A S6ng diQn tu ld s6ng ngalg n Khii6ng diQn tu lan truyAn, vecto cudng d0 diQn trucrng lu6n vudng g6c v6i vecto cim tmg tit C Khi sOn! Aign tu lan truyAn, vecto cubng d0 diQn trudng ludn cirng phuong v6i vecto cim rlng tu D S6ng dign tu lan truyAn dugc chAn kh6ng CAu Zlfni mic tr,r Cr vdo m4ch dao dQng thi m4ch thu dugc s6ng c6 bu6c s6ng 1.1 = 100 m, thay C1 bing tu Cz thi m?ch thu duo c s6ng ?uz:75 m Vdy mic hai tU n6i ti6p vdi r6i mic vdo mach thi m4ch b6t dugc s6ng c6 bu6c s6ng li: C.50m D.60m B.30m A.25 m nOn dao d6ng diOn trO R 0,01f), mach c6 Do = Ciu 3: M4ch dao dong LC c6 C = O,2 trtF,L = mH mach t6t ddn Dd rri dao dong v6i hieu diOn thdcuc d4i gifia hai bin tu diOn le U0 - 12V thi phAi cung cdp cho mach m6t cOng sudt llL B.P=42.10"5W A.t= Z4.IAI"W C.P=64.10-6W D.P=72.I0'6W Ciu 4: Trong mQt m4ch dao dQng LC lf tu