2015/2016
1
S , M1 M2
d=M1M2=3,4cm =100µs τ . 1- V1 . 2- (echographie) ,
V2=1500m/s : - V1 V2 . - t t=20µs .
L S. 2
20KHz
v=340m/s 1- )0,5(
= 83kHz N t=36ms 2- T λ . 3- K . 4 - ζ=20ms . d
. 5- V’=36Km/h
.
N=8KHz
air
=4,25cmλ λ
eau
=18, 75cm 6 – 7 – .
3
20KHz
. 1- . 2- .
E R
1
R
2
E
.
R
1
R
2
.R
1
R
2
Y
1
Y
2
) 1 .(6.10
-6
s/div
R
1
R
2
4cm
R
1
R
2
.
R
1
R
2
R
2
R
1
6,55cm
3- R
1
R
2
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كشــ ل
GBF
d
R
1
(Δ
R
2
0
كش
ـ
ل
di
4- T R
1
R
2
N 5- λ V
air
6- R
1
5 ,02cm
H=15,3m
. .
V
air
m/s V
eau
=1500.
.h .
A x
A
=0m B =50m x
B
)3 .(
t ∆
) 4 ( A
,
. 20ms/div 7- 8- t∆ A . 9- h ∆t H V
eau
V
air
. 10- ) 5 ( ∆t=f(x) t∆ x A B
x . 4
) 1 ( R1 R2 d. ) 2 ( d1=41cm : .0,1ms/div 1-1 - R2 1-2 N . 1-3 - R2
R1 R2
d2=61,5cm . 2 - λ=-d1 d2 λ . - V. - ζ R1 R2 2 - R2 ,R1 R2 92.25cm=d3 2-1 - d1=(k-n) λ + λ/ 2 d3 n k , K>n 2-2 – 2 R1 R2 3- a=7cm ,
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