Exemple de Devoir Surveillé

Li
LiOi
f0
iFiF0 i
1
OA0−1
OA =1
f0γ=A0B0
AB =OA0 OA
F0A0.F A =−f02γ=A0B0
AB =F0A0
F0O=F O
F A
L1
0< O1A<f0
1
L1
L1
L2
L1
A1B1
AB L1 −→ A1B1
L2
−→ A0B0

f0
1O1A γ1=A1B1
AB
A1B1L1
L2A1B1L2
f0
1f0 2O1A
O1O2
γ1
α0
αref
dm= 25 cm
G=α0
αref

A
i
i'
r
r'
J
I
B
C D
α
α

c= 340 m.s−1
p1(M, t) = A1(M) cos(ωt)
p2(M, t) = A2(M) cos(ωt +φ(M))
φ(M)r1, r2λ
A1(M)A2(M)
A1=A2=A0
I(M) =< p2(M, t)>
I(M)I0φ(M)
cos(a) cos(b) = 1
2(cos(a+b) + cos(a−b))
 << 1√1 + '1 + 
2
δ(M) = r2−r1
z(x, t) = Z0cos(ωt +φ) sin(kx +ψ)
ω=kc c
ψ knn
L

O1O2
Ox
y
M
r1
r2
d-d 0
x
D
Banc de déplacement
du microphone
z
x
0 L
λnfn
n, L, c
f1= 110 L= 63
z(x, t) cos(ωt +φn)=1
φ φn
f1