גלים מכניים ואלקטרומגנטיים
✦ בנוי על ידי פהד גאנם ✦
العربية
☀ מצב בהיר
3.1
▾
✕
y(x, t) = f(x − v·t) | v =
Δx
Δt
| Δt =
w
v
| v
y
= −v ·
∂y
∂x
0.30 m
0.60 m
6.0 m/s
5.0 m
0.0
0.00
0.000
0.00
0.000
0.00
0.00
Δt =
w
v
Δt =
w
v
=
0.60
12
= 0.050 s
v
y
= −v ·
∂y
∂x
v
y,max
=
π·A·v
w
=
π·0.30·12
0.60
= 18.8 m/s
3.2
▾
✕
v = f·λ | T =
1
f
| λ =
v
f
L = n·
λ
2
| λ
n
=
2L
n
| f
n
=
n·v
2L
= n·f
1
0.20 m
0.80 m
1.00 Hz
1.20 m
2.00 m/s
1
2.00
0.80
1.00
1.000
2
1
0.833
λ =
v
f
=
2.0
5.0
= 0.40 m
T =
1
f
=
1
5.0
= 0.20 s
L = n·
λ
2
⟵ λ
n
=
2L
n
λ
1
= 2·1.2 = 2.4 m
f
1
=
v
λ
1
=
2.0
2.4
= 0.83 Hz
3.3
▾
✕
v = λ·f
|
λ =
v
f
|
sin θ₁
sin θ₂
=
v₁
v₂
=
λ₁
λ₂
0.15 m
0.20 m/s
40°
52%
0.15
0.10
0.30
0.20
2.00
40°
—
—
v = λ·f λ =
v
f
λ₁ =
v₁
f
=
0.30 m/s
2.0 Hz
= 0.15 m
λ₂ =
v₂
f
=
0.20 m/s
2.0 Hz
= 0.10 m
3.4
▾
✕
Δr = d·sinθ = m·λ | Δy =
λ·L
d
1.60 cm
3.0 cm
600 nm
0.10 mm
2.0 m
12.0 mm
0
0.00
0
0
λ = 600 nm = 6.0·10⁻⁷ m
d = 0.10 mm = 1.0·10⁻⁴ m
L = 2.0 m
d·sinθ = m·λ
Δy =
λ·L
d
Δy =
λ·L
d
=
6.0·10⁻⁷ · 2.0
1.0·10⁻⁴
= 1.2·10⁻² m = 12 mm
y₃ = 3 ·
λ·L
d
= 3 · 1.2·10⁻² = 3.6·10⁻² m = 36 mm
3.4
▾
✕
סריג: d · sinθ = m · λ | d =
1
N
| sinθ =
m · λ
d
550 nm
2.0 µm
600
0
0
0
0
0
d =
1
N
=
1 mm
600
= 1.667·10⁻⁶ m = 1.667 µm
d · sinθ = m · λ → sinθ =
m · λ
d
sinθ₁ =
1 · 550·10⁻⁹
1.667·10⁻⁶
= 0.330 → θ₁ = 19.3°
m
max
=
d
λ
=
1.667·10⁻⁶
550·10⁻⁹
= 3.03 → m = 1, 2, 3
3.5
▾
✕
c = λ·f = 3.00×10
8
m/s | λ =
c
f
| E = h·f =
h·c
λ
—
—
—
—
—
—
λ =
c
f
=
3.00×10
8
1.00×10
8
= 3.00 m
E = h·f = 4.136×10
−15
· 1.00×10
8
= 4.136×10
−7
eV
E = 6.626×10
−34
· 1.00×10
8
= 6.626×10
−26
J
f =
c
λ
=
3.00×10
8
550×10
−9
= 5.455×10
14
Hz
E = h·f = 4.136×10
−15
· 5.455×10
14
= 2.26 eV
E
green
E
radio
=
2.256
4.136×10
−7
= 5.45×10
6
→
🏠
♿