Cdu 11: M o t v a t dao dong dieu hoa c6 chu k i l a T N e u chon goc thcfi gian t = l a luc v a t qua v i t r i can bang, t h i t r o n g nufa chu k i dau t i e n , van toe cua v a t b k n g k h o n g of t h d i diem: T A t = - B.t=I C.t= T - D I Giai Chon goc t h d i gian t = l a luc v a t qua v i t r i can b k n g , t h i — chu k i nufa v a t se tcri b i e n v a v a n toe b k n g k h o n g T r o n g nufa chu k i dau T tien, v a n toe cua v a t b k n g k h o n g d thdi diem t = — Vdy chon dap an B Cdu 12: M o t l a t h e p mong, m o t dau co d i n h , dau l a i diJtfc k i c h t h i c h de dao dong v d i chu I d k h o n g doi va b k n g 0,08 s A m l a t h p phat r a l a : A sieu a m B am C nhac a m D a m m a t a i ngifdi nghe diftfc Giai T a n so a n t h e p p h a t r a : f = - = — ^ = 12,5 < 16Hz T 0,08 T a i ngifori k h o n g t h e nghe di/grc a m co t a n so dtfdi 16Hz n e n a m la thep p h a t r a l a h a a m Vdy chon dap an B Cdu 13: P h a t bieu nao sau day l a s a i k h i n i ve p h o n g x a (hoat d6 phong xa)? A Dcfn v i do phong xa l a beccfren B Do phong xa l a d a i luang dac trifng eho t i n h p h o n g xa m a n h hay yeu cua m o t li/cfng chat phong xa C Vdri m o i iLfotng chat phong x a xAc d i n h t h i dp p h o n g x a t i le vdri so nguyen tuf cua liTcfng chat D E)o phong xa cua m o t lacfng chat ph6ng xa p h y thuoc n h i $ t dp cua lUtfng chat Giai Do phong x a cua m o t li/tfng chat phong x a k h o n g p h u thuoc v k o cdc tac dong b e n ngoai nhtf n h i e t do, ap suat, a n h sang, Vdy chon dap an D GIJichitiStdlthiTSDH, CDMdn V l L t l f