Cdu 10: K h i n o i ve dao dong ctfSng bufc, phat bieu nao sau day la diing? A Dao dong so cua life CLfSng ciTSng bufc c6 b i e n k h o n g doi va c6 t a n so b^ng t a n bufc B Dao dong cua l^c dong ho l a dao dong ctfSng bufc C Dao dong CLTorng bufc c6 t a n so nh6 hcfn t a n so cua life D B i e n cua dao dong cif5ng bufc la b i e n cua luc cifofng cU9ng bufc bufc GiSi Theo d i n h n g h i a , dao dong t ^ n so b k n g t a n so cua ciTSng liTc ciTofng bufc c6 b i e n k h o n g doi va c6 bufc Vdy chgn dap an A Cdu 11: K h i n o i ve dao dong dien tii t r o n g mach dao dpng L C l i t t r d n g , phat bieu nao sau day s a i ? A N a n g lifpng ttf trifdng v a nSng lifcfng dien trircfng c u a mach luon cung t a n g hohc luon B N a n g lufcfng lifcfng cung giam dien tii cua mach gom nang lifgfng tCf triJcfng va nang dien trifdng C Cucfng dong d i e n qua cu6n cam va h i e u d i e n the giiJa h a i ban t u d i e n b i e n t h i e n dieu h6a theo thcfi giem v d i cung t a n so D D i e n t i c h cua m o t b a n t u dien v a cirofng dong dien t r o n g mach b i e n t h i e n dieu hoa theo thcfi gian Ipch pha ^ Gik\ N a n g l i r p n g tCr t n f c m g va n a n g lufpng d i e n t n r d n g cua mach lu6n b i e n doi ngufpc pha Vdy chon dap an A Cdu 12: M o t s6ng a m t r u y e n t r o n g k h o n g k h i MuTc ciXcfng a m t a i d i e m M va t a i d i e m N I a n lucft la 40 dB va 80 dB Cifcfng a m t a i N 16n hofn ci/cfng a m t a i M : A 10000 I a n B 1000 I a n C 40 I a n D Ian Gi4i Goi lo l a Mufc cirdng CLTcfng L, a m t i e u I i , I2 la chuin; a m t a i M va N I a n cUcfng d6 a m t a i M v a N lUcft l a : = / i - = 40dB;L2 = / g ^ = 80dB 32 ' Giai Chi fiSt 34 thi TS DH, CD M6n V$t 11