PP giai chuong III -12NC

A C B I D G H F E J          λ   λ                   !"#$%&'(&)*+,,+$%)$%-  ./01/23   4)56123 λ 47&8)90:       λ λ   = = =     3#;<4 6  =>?1@ABAA"CDEA"=FG11AD=/"EHF/1ID=/@/  2      ω π ϕ λ   ∆ = =     3#;J4   ϕ π ∆ =   !"!#$%& "'()* + [ ]   λ ⇒ = %,!  ∈ 3#;K4  - . ϕ π ∆ = +  !"!#$%& "'/(* +  ( )         λ λ     ⇒ = + = +  ÷       %,!  ∈ 3#;#4  - .   π ϕ ∆ = +  !"!#$%& "'%* +  ( )      0    λ λ     ⇒ = + = +  ÷       %,!  ∈ 3#;L4  /2/"CDEA"=MF11N2+D=/">GE  < GE J  1!23*45!6(45+ [ ] 7 7  -  .   ω ϕ = + ⇒  !"#$ %&'  7 7    -  .  -  . "          π ω ϕ ϕ π ϕ λ   = + − ∆ = + −     3#;O4 • &PQ() * + ,  ,  * -. / ' + H+;13R/ST + 4 . / + ,  *  , "0(1 2  * -. / '       π π ϕ λ π π ϕ λ    = + +  ÷         = + −  ÷     os os F +  + E  +;1 : ;/ E  +;1 : ;/ Mô ̣ t sô ́ điê ̉ m câ ̀ n chu ́ y ́ khi gia ̉ i toa ́ n: G>?>G==7&/U1GD=/0@@@V/ ./WQ<J7 A< 89 : (  (! ;  !"! : $(  * <=  >  ?  $ @   ?=  <  (   89 : (  (! ;  !"! : $ @ (*  <=  >  ?  $ @   ?A :  : <  (   ! ( B7CDE FCE  G  <;3*-45/*-/*))/*,67#6,//,*&8 9:;<=-> ?@'ABCD0E7BFG0H7 J;I8:;<=-J8K)L-0)K:)K@9"=>?1@A BAAEA"=;> K;MN. / ) /  * O) / P *  * -5 /  6 5 , 5 *   ) 6  6 ?P 6  * > #;QROS;K+TU0+S5+> L;?TV-WP4:U=!XK+>Y; K+;0TVZ[#\VX   [&> O;M * . / ) /  *  / K+ , ) / ]S>(] , !KP8KO=%4 -4)P !>Y^_ ] , :K\> X;Y * ) / 1K+ , -0)K+ ,  / ] 6  / +K * . / (` * +4 ,  6 K / 4)+ ,   *  , K , ) 6 K *  * ) /  / >V;4;0:a4)P +[%_#b(`+[&> H *+,,+$%  • &PQ  Y Z /[ \ 1 Z "]D1 \ " ^ 1 ^ 1"A ^ >A _ " _ // ^ 11 ] A+5A _  ^ " _ @> /`] \ /a ^ +M5>A _ D/"]D; Y Z /[ \ 1 Z "]D1 \ " ^ 1 ^ 1/]>A _  ^ " _ @>" \ / \ /a ^ +M5>A _ D/ "]DM`_Db8 Z  \  Z A \ @>1 ^ 1"A ^  YcA ] 1A \ 1 Z AA ^ AA \ / \ >/\@A`_ ] A \ 1 \ ; • Giao thoa – Điều kiện để có giao thoa:  Ic<[S-XaS-+0JdK4) PP#[S-&<!<8>  ef=SO^:%;aS->I; L\VP=- Xg+[1> <; ANEA"=1I@A 3d//e11fAAN+M5>G EdEA"=1e1"4 1!23*4(J  !64%&G "'() * + [ ]  -  .  -  .  h         ω π = = = KL5!"!#$(M($'>2   "= C(M(G$'>2   h"= 45!>!4NO,!+      -  .  "       π π λ →   ⇒ = −     G>?>G==7&/U1GD=/0@@@V/ ./WQ<J7 AJ  G   λ G    G   λ  λ  45!>!4NGO,!+      -  . h "       π π λ →   ⇒ = −     A4 /2/gh@/"CDFEAN2+G5//6         - .    - . "  " h "             π π π λ λ → →     ⇒ = + = − − +          -0P. 4 5"=1fA2/gh@/F         ∆ = = −     F + +; 1 +; 1 3 E E 4 ϕ π λ -0D. 14 =>?1@A1fAA2/"CDF        3 E E 4 3 E E 4  ω π ϕ λ   ∆ = − = −     6   ∈ 3#;i4 • &PQ  CDEA"=1e1"+ DAb HJ+       ∆ = − =     3 E E 4 8 π ϕ π λ  [ ]   ⇒ − =E E 8 λ 6   ∈ 3#;<j4 ⇒ Tại những điểm này hai dao động thành phần cùng pha và biên độ dao động của sóng tổng hợp cực đại.( d@>/C?kl/>/m) CDEA"=1e1/C+ D Hj         ∆ = − = +     3 E E 4 3 8 4 π ϕ π λ         ⇒ − = + = +E E 3 8 4 3 8 4 λ λ 6   ∈ 3#;<<4 ⇒ Tại những điểm này hai dao động thành phần ngược pha và biên độ dao động của sóng tổng hợp cực tiểu.( d@>/C?kl/"U//m). ∗ d"CDEA"=/=1"//e1Xh8KP%"=1e1"R 1e1"//aDb%8Hj ⇒ @<!4TD'  = ± >@<!4T'  = ± nEo'?5<!4TH' D = ± BY+<85K)' ⇒ @<84TD' 7Q  = − >@<84T' Q  = − − nEo'?5<84TH' PQ D = − E4 Fp$qr,s tu's*v*  DẠNG 1: G!>2(M(N"!#$,!6?R?/?&  C  S5! "'%,!<!"' (T("5! 1!U %,! "VT((J G(4W(T("5!>M(S$%X(Y-"O<&!Z($'"5!?/. @@ SKM("[<\(9(J W(T("5!5!+ c ]B B^*_(`(("!#$ "'(T("5!+     E E c c ;; c : λ − = = = Ba "5!?/(R$+%X(Y DẠNG 2: G!>2(M(N"!#$,!6?R?/?&  C  KM("[b(c(J "!#$ "'d <! λ X(%%&Y @@ Be\*fg+   E E  ε λ − = + S"4+?&*RQ ε ?&*R\**= G>?>G==7&/U1GD=/0@@@V/ ./WQ<J7 AK  B 7 ε = ?&"!#$'(W "'cực đạiBậc K= n B 7 hM ε = ?&"!#$'(W "'cực tiểuBậc n + 1 DẠNG 3: G!"'?i(* (J  !6()O,!"!#$()$'*O4>2(M(N "!#$,!6?R?/?&  C  KM("[>2(M(X( λ C%%&Y @@ Ba3_(`(+ ( ) ( )      ; E E ; E E 3 4    − ∆ = − = ∗     ω π ϕ λ 7  "'()*  c ϕ π ∆ =  %& 3 4∗ ⇒ "5!?/(R$ 7 "'/(*  ( )  c ϕ π ∆ = +  %& 3 4∗ ⇒ "5!?/(R$ 7 "'%*  ( )    c π ϕ ∆ = +  %& 3 4∗ ⇒ "5!?/(R$ • &PQ+ 7cA ] 1A \ 1 Z AA ^ 3"CDEA"=1e1"4AA \ /3"CDEA"=1e1/C4 \ >/\@ A`_ ] A \ 1 \   >  λ = DẠNG 4: KM("[%[b%&g"!#$ "'(T("5!"5G-H,!%&G?& !64. @@ B1j!?&"!#$ "'(T("5!"5G%&(M(CG?R?/U"5  C  S (4+        E E c +5 c E 3 4 E E +5 λ λ + =    ⇒ = + ∗    + =    Bk  7 E +5≤ ≤ 9/*%,! 3 4∗ a + +5 +5 c λ λ   − ≤ ≤      3 4∗ ∗ %,! c w∈ • &PQ + • dM("!#$ "'(T("5!"5G-b(2 !"!#$%&G%&G?& !"!#$ "'(T("5!. (b?&!Ml(M(!M[9m $W(`( 3 4∗ ∗ • H[b(M("!#$ "'(T("5!nM("[<o(`( 3 4∗ DẠNG 5: KM("[%[b%&g"!#$ "'(T(!#"5G-H,!%&G?& !64. @@ B1j!?&"!#$ "'(T(!#"5G%&(M(CG?R?/U"5  C  S (4+           0 E E c +5 E 3 c 4 3 4 E E +5 λ λ    + = +     ÷ ⇒ = + + ∗         + =  Bk  7 E +5≤ ≤ 9/*%,! 3 4∗ a +     +5 +5 c λ λ   − − ≤ ≤ −      3 4∗ ∗ %,! c w∈ • &PQ + • dM("!#$ "'(T(!#"5G(b?&!Ml(M(!M[9m $W(`( 3 4∗ ∗ • H[b(M("!#$ "'(T(!#nM("[<o(`( 3 4∗ • &2/CEI1/U1A311J4"CVE#GEL &1Jxb1"y0"CDEA"=1e1"G1e1/C/"+5 `T-OV-5i!' G>?>G==7&/U1GD=/0@@@V/ ./WQ<J7 A#    = +     h  j λ "2@9#%,!   (∈ .QK@9/.@@a FQV8KP1e1")!kh'#+Vl& [ ]  ; + 3xzHj/A"CD+M5>GA"CDEA"=1e1"4 SQV8KP1e1/C)!kh#+Vm& [ ] [ ] 7 h   7 h M ; ; z M  <   + ≥   2n neáu X neáu • &PQxb1"y0"CDEA"=1e1"G1e1/C/8V+5 B$0EA"=1e1"+  J;)<3xzHj4  J;S<3xz ≠ j4 S$0"CDEA"=1e1/C/e/ [ ] [ ] 7 h   7 h M ; ; z M  <   + ≥   2n neáu X neáu J; AEA"=h1@A 3d//e11fAAN+M5>GEdEA"=1e1/C4 !-  . !-  .Q ω π = =        %& !-  . !-  .Q ω π π π = + = + h       A4 5"=1fA2/gh@         + A;  3 E E 4 A; 1 3 E E 4 π π π λ λ     = − = − +         3#;<J4 4 CDEA"=1e1"         E E 3 8 4 3 8 4 λ λ   − = + = +     3#;<K4 14 CDEA"=1e1/C  [ ]   E E 8 λ − = 3#;<#4 E4 $0"CDEA"=1e1"G1e1/C h1b1"yh1>6111/U18ANEA "=1I@A  AEA"=@A  !-  . !-  .Q ω π = =        %& !-  . !-  .Q   π π ω π = + = + h       A4 5"=1fA2/gh@        0 0 + A;  3 E E 4 A; 1 3 E E 4 π π π π λ λ       = − − = − +             3#;<L4 4 CDEA"=1e1"    0 E E 8 λ λ   − = +     3#;<K4 14 CDEA"=1e1/C  ( )      0 E E 8 λ λ   − = + +     3#;<O4 E4 $0"CDEA"1e1"k60"CDEA"=1e1/C    0 0 +5 +5 c− − ≤ ≤ − λ λ 3#;<X4 $% - Ia    ?  ! @  @ !  ! ;     !%    * : n @ (  $ @ %= @ "    ! @    G>?>G==7&/U1GD=/0@@@V/ ./WQ<J7 AL YcA ] 1A \ 1 Z AA ^ ` ^ 1A \ />/\@A`_ ] A \ 1 \ ; YcA ] 1A \ 1 Z AD ^ / ^ A _ D ^ / \ />/\@A`_<{# \ 1 \ ; 0 λ λ G   @ "=  (  "! @   λ  λ G   @ "=<! @ >p  qr<,(4 s !"=<! @ >p  q<,(4  !"=tqu<,(4   ; %! @ p  (  "! @ (  <!" @  " @ ( @ (" @ !-< @   .%   ; "! : $> " @ -    . e  + Ba    (  " @ (! : ?    (  (  (  %  (  (< @ 1\ " ^ /8A B1!,!510"y⇒ P/2 B1!,!5/eE⇒ 5o2 BN*M4⇒ "/((!R"v?&P/2 BGO'<_40 -%,! ?&<!"' "'(J 6. <; A"9Ea10"y + A4 Điều kiện về chiều dài  h= của dây có sóng dừng+     ;  +5 >   ; :   = = = =     λ %,!   (∈ 3#;<L4 4 Số nút và số bụng sóng+  f8Kg +agv4!Og<_$'"%[ Bag<_4]g<44] Bagv4]B  f8K4W +ag<_4!Ogv$'"%[ Bag<44]F Bag<_4]B Bagv4]  F=/"910"yD=/"9/eE ag<_4]gv4 A4 Điều kiện về chiều dài  h = của dây có sóng dừng+ ( )   0  0 λ λ λ = = + = ++5 >   %,!   (∈ -0w.  0 λ = D %,!m = 1, 3, 5, 7… 4 Số nút và số bụng sóng+ Bag<44] Bag<_4]gv4]B Mô ̣ t sô ́ điê ̉ m câ ̀ n chu ́ y ́ khi gia ̉ i toa ́ n: <; 3 * ) 6 nW;=:R8:;o o<U KPS-XR> J; 3;\VpXS5;g * 0\+Vp#<&4W> 3. 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