D i l m sang S qua L cho a n h S ' each L m o t doan: da = 12 + = (cm) Muon chum t i a qua L la chum song song t h i S ' p h a i n a m of t i e u diem F2 cua L , hay t i e u cU cua L la £2 = da = c m = 0,36m 1 25 Dp t u cua t h a u k i n h L p h a i c6 gia t r i : D = j = Q~3^ ~ "9" (^^°P^Viay chon dap an C Cdu 45: M o t k i n h h i e n v i quang hoc gom v a t k i n h v a t h i k i n h c6 t i e u cLf I a n luot l a 0,5 c m v a cm K h o a n g each giufa v a t k i n h v a t h i k i n h b^ng c m M o t ngUdi m ^ t k h o n g c6 t a t , c6 d i e m ctfc « a n each m ^ t 25 cm, suT dung k i n h h i e n v i de quan sat m o t v a t nho D o b p i giac cua k i n h k h i n g ^ m ehCrng d v6 cufc la: A 19,75 B 25,25 C 193,75 D 250,25 Giai T a c6: D = c m , fi = 0,5cm, {2 = c m , = - 4,5 = 15,5cm Do boi giac cua k i n h k h i ngim ehCfng d v6 cifc 1^: G = = 193,75 hh Vay chgn dap an C Cdu 46: M o t t i a sang dcn sic t r u y e n tii m o i trir&ng (1) c6 ehiet suat tuyet doi n i sang m o i trifcfng (2) c6 ehiet suat tuyet doi na t h i t i a k h i i c xa lech x a phap t u y e n hcfn t i a tdi H i e n ti/png p h a n x a t o a n p h a n c6 the xay r a k h o n g neu chieu t i a sang theo chieu tii m o i trifcfng (2) sang moi trifcfng (1)? A K h o n g t h e , v i m o i triX&ng (2) ehiet quang hcfn naoi triTcfng (1) B C o t h e , v i m o i trifofng (2) chie't quang k e m m o i triTcfng (1) C C o t h e , v i m o i trifcfng (2) ehiet quang hcfn m o i triTcfng (1) D K h o n g t h e , v i m o i trUcfng (2) ehiet quang k e m m o i tri/orng (1) Giai K h o n g t h e , v i m o i tnicfng (2) ehiet quang k e m m o i trifcfng (1) Vay chgn dap an D Cdu 47: M o t ngifcfi can t h i c6 d i e m cife can c ^ c h m ^ t 10 c m , d i e m ciic vi§n each m ^ t 50 cm, deo k i n h eo t u - diop s t mAt t h i n h i n ro vat: A each mkt c m m ^ mSt k h o n g can dieu t i e t B d gan n h a t cdch m ^ t m o t doan 10 cm C or x a v6 ciTe nhiftig m ^ t v a n can dieu t i e t D d x a v6 cue m a m ^ t k h o n g can dieu t i e t GtSi Chi t i ^ t t h i T S D H , C D M6n V $ t If 21