ĐỀ THI CHỌN HỌC SINH GIỎI TỈNH LỚP 12 NĂM HỌC 2012 – 2013 MÔN VẬT LÝ LỚP 12 THPT - SỞ GD&ĐT NGHỆ AN

ĐỀ THI CHỌN HỌC SINH GIỎI TỈNH LỚP 12 NĂM HỌC 2012 – 2013 MÔN VẬT LÝ LỚP 12 THPT - SỞ GD&ĐT NGHỆ AN

SỞ GD&ĐT NGHỆ AN (Đề thi có 01 trang) KỲ THI CHỌN HỌC SINH GIỎI TỈNH LỚP 12 THPT NĂM HỌC 2012 – 2013 Môn thi: VẬT LÍ 12 THPT - BẢNG B (không kể thời gian giao đề). Câu 1 (5,0 điê ̉ m).         !"  # $%  &   '"    !$()*"  +  ,-  . '  %'/-0123   +#    '# 4  '567 . 8- 9  :  ;$*9 < =+ '>  + ,     &  " ' (%,"   . &   ,-  '" ?&# . '  %"  ?# . + ,    %>  -0##   >+  "  #  @$A-   . +    + 0'" '>  -  +  +>  #,  0'" - . +  <  #  '> .    &  " ' B%    B+  8-C'#  +D''#  '>  #  '> . '  E B>  > . -   '  "  - .     0- >  '# 4 &#   (  '" #  + "  - . + # . + ,     &  " ' %E Câu 2 (5,0 điê ̉ m). ,>    .   -"    9  !>  # F%7  -<0'G+#  #,   F 7 - <9< @A%- <9@<  A@A = π = π + π "  '" ,-;>  9  +$%H*9>'" 9   !"'" .  >  #,  9   '5I,>JKL  F%7  IF$M%I7$< <%N  '> . ,> KL9F7N     4    FN$O  ' 9"  '> . 0'"  ' ,>' F7+  ' 7NE BI  %I <   '> . ,>' F7  F  # <+  (O  ' '" > 0 '" - . I  +  I < E (P Q  ,-'> . - . ' NO  ' '> . ),>N  Q  0'"  ' E Câu 3 (5,0 điê ̉ m). '  ;>  -  <= +  '  -F%7'>   ;>  - F7 -  < 9@  A@A < π = π − 7>  -G0;R  : @SA%, <@ A B = = Ω π TU'VR ( B  @WA < − = π T X,YZ =[-\Z]  Z ^@ A= Ω  >  > . -  #  '" 0  '> 8-  >  > . -  '>    I7 -  <=[-\Z] < Z '> . "9-  >-- ,>'  F7 ' _ < Z E Câu 4 (3,5 điê ̉ m). I" + 9   . % . F7'# ' ,>,-   +  +-"  +#  ,-   ,1"   - !  !  `R!a1]*B+Db+c,a'/-% 4 + "  ' %0 -;> .   -!   " ' 0 &,-   @da'/-'e+1+DA   .   *<+    >- - .   -!  E <F . - . + 0 -;> . '   >-E Câu 5 (1,5 điê ̉ m). I" 0;'"  %'#  !  0$%<  - . " #  9#  '>  . '# 8-    )+   >  9  -'> .    " "  0;0%  >  -0  +  '#  !  N$0  '> R 'GQ  $Ff;8-e0;%9-'R    '  -0;- . "  ! . -"  S 4 ;  ' '> #  -;> . 8-"  0;!> .   -    '  -  '> E>  '> ,# . 9-  - . '"   ^ %g @ A − ρ = Ω  - - - Hết - - - Đề chính thức  S_ ! 6 7 Z S_<  F :%, I Họ và tên thí sinh Số báo danh  SỞ GD& ĐT NGHỆ AN KỲ THI CHỌN HỌC SINH GIỎI TỈNH LỚP 12 THPT NĂM HỌC 2012 - 2013 HƯỚNG DẪN CHẤM ĐỀ THI CHÍNH THỨC I" VẬT LÍ 12 THPT - BẢNG B @Hướng dẫn chấm gồm 04 trangA Câu Y ́ Nô ̣ i dung Điê ̉ m 1. (5,0đ)  h . 7  &  " '     <%@A ! ∆ = =  %<  # . + ,     '" &' - QQ)-# %%  !@  A  ∆ − − = %% %% < ! !      ⇔ − = ⇔ = − = −ω   ;+ 0'" '>  -     ! <@,0 * 9A  ω = =  %g i#,  0'"   0   F9@  A= ω + ϕ % +  F9@  A⇒ = = −ω ω + ϕ  $       F9   < + F 9  = ϕ = ∆ − ∆ = −   = − ω ϕ =  F < @,0A =  ⇒  ϕ = π  %g  ;#,  0'"     <9@< A@A= + π  %< <  '"    &   j      @A= ∆ − ∆ = − %-!   <  @9A  π π = = ω %<   "  >>  4 0'" '>  -  +  -;> . '" ,  '>  -  ;+ 8- + ,     '"       B+  #  '> .   B   B   @9A %BM@9A < H H − π = + = ≈  %g 6- 4 '#  + ''# 'X'5'R F k g(F Bg@A < = + =  % B : '  "    0- >+ W ' $l$  %^9@< A@)A − + π  % : '  "  0    0- >  6 j 0 0 W W %^9@< A @)A= − = + π −  % (  '" - . +    &  %$<%m%$ %< =" #  + "  - . +  < < + F  < B@A= ω − =  %< 2. (5,0đ)  i#,  9   I0F+  7,-;>  '>    < I <I < 0 < 0 -  9@  AT- 9@  A π π = ω − = ω − + π λ λ % 7#  9   + %H H n λ = = = %< i#,_9RfI  I I <I  <  < - - - <9 @0 0 A 9  @0 0 A < < π π π π     = + = − + ϖ − + +     λ λ      % S; I - (9@<  B A@A= π − π %< < => . 0'"  '  .  4   <  <  9 @0 0 A  0 0 @! A @! oA < < π π   − + = ± ⇒ − = − λ ∈   λ    % p,>' F7 % <  <  <  F7  F7  0 0 @! A @! oA ! < < < 0 0 F7 ! o   − = − λ ∈ − + < < +   ⇒ λ λ     + = ∈  k-;,!$m<TmTTT<TBS;  H'> . 0'"  ' ,>' F7 p,>' 7N k"  '> . 0'"  '  .  4   < FN 7N 0 0 F7 − ≤ − < %@+#  7N$<A   FN 7N @! A F7  @! A < < < ! o ! o   − ≤ − λ < − ≤ − λ <   ⇒ ⇔     ∈ ∈   k-;,!$mTTT<TBS;  '> . 0'"  ' ,>' 7N % B I    F+  70  $<+  0 < $^TI <   F+  7 j  0 $(+   j  0 $H %< i#,_9Rf  I      I I < I < 0 - <9@<  A <  - (9@ A9@<  A < 0 B < H - <9@<  A π  = π −  π π π  λ ⇒ = + π −  π  = π − + π  λ  @A S;  I  - < B9@<  A H π = − π − @A %< i#,_9Rf < I  < < < j  I I j < <I < 0 - <9@<  A (  - (9@ A9@<  A B < H < 0 - <9@<  A  π = π −  π π π  λ ⇒ = + π −  π  = π − + π  λ  @A S; < I  - < B9@<  A H π = π − @A %<  ;I  +  I < 0'" -  >'" %# -S;'" > 0 '" - . I  +  I <    @,0A ∆ϕ = π %< ( => . )  Q  0'"  '  .  4 0  m0 < $ λ *<$B@A@A     +& 4    < < < < <  < < < < < < F7 0 FN N) FN @ A < F7 0 7 ) FN @ A <  = + = + +     = + = + −   < < < <  < F7 F7 0 0 @ A @ A <F7 ( < < ⇒ − = + − − = = @<A %<   @A+  @<A  < ( ( 0 0  B + = = λ @BA %<   @A+  @BA < <   (  < B < B B < 0  0 @  A < B < B < λ + = = + ⇒ = + @(A I !   < < < < < < <  F7 0 FN N) FN @ A  @ A < = + = + + = + + @A %< k9  @(A+  @A%   < BM  B<<%g  <%gB@A M = ⇒ ≈ q>  -   <'> .   Q  0'"  ' @'"    -8-QA %< B ? ) Q  N 7 F 3. (5,0đ)     :     < o : @ ATo @ A%Z Z ^@ A  B B = ω = Ω = = Ω = = Ω ω  %< " . ,# .  < <  :  < o @Z ,A @o o A @ A B = + + − = Ω  %< =" >  4 - F7 +   :  o o   @,0A Z , H B − π ϕ = = − ⇒ ϕ = − +  %g k-;, -   - @,0A B π ϕ = ϕ − ϕ ⇒ ϕ = ϕ − ϕ = −  %< I !     r H Q @FA o < = =  %<  ; H  9@  A@FA < B π = π −  %<     < < < I7  : I7  I7 < o @Z ,A o @ A r Q o < <@A B = + + = Ω ⇒ = =  % =" > - . - I7 9+#   : I7 I7 o   @,0A Z , H B π ϕ = = ⇒ ϕ = + % k-;, -@I7A I7  @,0A H B H π π π ϕ = ϕ + ϕ = − = − %<  ; I7 - < < 9@  A@A H π = π −  %< < "9-  >-- ,>'   < < < < < < :  :  r @Z ,A r i Q @Z ,A @o o A @Z ,A @o o A @Z ,A Z , + = + = = − + + − + + +  %g   ;i  ! < :  < < :  < @o o A @Z ,A Z , o o Z , − + = ⇒ + = − +  % k-;, < :  Z o o ,= − − =  <@ A Bg%g@ A B − Ω ≈ Ω  %< 4. (3,5đ)     . 9-!0 -;> .   !  #   . #>  -!  ' 4 0 -;> .  ,+ >  0 < $0  l@A@A %g k"    '  . -  '  -   n  q n 0 < = = − @<A % k"    '  . 9-!0 -;> .   -!   < < n  q n 0 B = = − @BA %   @A%@<A+  @BA9-;,n$m@A %g <     0 @A= % < 0 <@A= j j     0 q 0 @A 0 = − ⇒ = − T j j < < < < 0 < q 0 @A 0 B = − ⇒ = − % F . 0 -;> . " '  j j j < <   < 0 @0 0 A @0 0 A @A B ∆ = + − + =  % 5. (1,5đ) q  '> %,"  0;-  > 9-  '> '"   . &  0'    0   '> 8-"  0;  & Q Z = => # -;> . 8-"  0;,#     8∆ $Q  ∆ $  &   Z ∆  %< ( #   <   & 8 8  Z Z φ − φ∆φ ∆φ = − ⇒ ∆ = − ⇒ ∆ = − ∆ %< < φ     "8-"  0;!Q$9-;, < φ $  φ     "8-"  0;!Q$Q  9-;,   :Qφ =   :Q 8 Z ⇒ ∆ = @A %< ="  +#  " "  0;  4 DN S N L 22 0 2 0 π µ=µ= @<A I !  '> ,# . "  0; 2 d 4 S R π ′ ρ= ′ ′ ρ=  @BA %< ;@<A+  @BA+  @A'#  ∆ 0 2222 0 I 16 DdN q  ′ ρ π µ= @(A #  >  -0  0; DN π= ′  (5)%>  -0  "  0; Nd =  (6) %< ;@A+  @HA+  @(A'#  < ( g (   ^ N0   <  8 Q (   %(   H H %g  − − − − − π π× × × × ∆ = µ = π× × ≈ × ρ × × %< - - - Hết - - - Chú ý: Nếu học sinh giải cách khác đúng vẫn cho điểm tối đa.  . VẬT LÍ 12 THPT - BẢNG B @Hướng dẫn ch m g m 04 trangA Câu Y ́ Nô ̣ i dung Điê ̉ m 1. (5,0đ)  h . 7  &  " '    . ,     &  " ' (%,"   . &   ,-  '" ?&# . '