1. .
2. .
3. .
, , .
, , :
S 1 = A cos (ω t-kx), S 2 = A cos (ω t+kx+φ),
S 1 S 2 , , t; ω (ω = 2π/ , ); ; k (k = 2π/λ, λ ); φ .
:
S = S 1+ S 2 = B cos (ω t+ φ/2), (1)
:
B = 2 A cos (kx+ φ/2). (2)
(2) , .
, , , . , , , , B max=2 A, - .
( ). (φ = -π). .
φ = -π (1) (2), :
S = B sin ω t, (3)
B = 2 A sin kx. (4)
. (4) = 0. sin kx = 0, , kx = mπ, m = 0, 1, 2 ,
x = mπ/k = m λ/2 = 2 mּ (λ/4). (5)
: B = B max= 2 A. - , . , sin kx = 1, kx = (2 m + 1)π/2. :
x = (2 m + 1)π/(2 k) = (2 m + 1) ּ (λ/4). (6)
(φ = 0) , φ = -π. , λ/2, λ/4.
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, , , ..
1.
L, . V. . , . λ/2, (L = m λ/2), , λ =2 L / m (m = 1, 2, 3 ). λ = V/ ν, :
ν = V /λ = mV/ (2 L). (7)
, , , .
:
(8)
F, d, ρ , . (7), :
m = 1, 2, 3 (9)
ν1 (m = 1) . , ν1, .
.1 , (m = 1) .1, (m = 2) .1, (m = 3) .1.
. , , .
. : , , , .
, . , . . , . . , .
1. .
2. L, d ρ ( ).
3. 3-5 F ( ) νm (3-5 , ν1 , F). F νn 1. .
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