Test

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35-2. Light as a Wave
Two waves of light of wavelength 400 nm are
initially in phase. n1 1.6, n2 1.5 What is
the smallest value L, if the waves are to end up
with a phase difference of 5.65 rad?
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35-4. Double-Slit Interference

• Constructive Interference

• Destructive Interference

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35-4. Double-Slit Interference
Red laser light (l633nm) goes through two slits
1cm apart, and produces a diffraction pattern on
a screen 55cm away. How far apart are the fringes
near the center?
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35-4. Double-Slit Interference
The separation between the slits is 0.5mm and the
first order maximum of the interference pattern
is at an angle of 0.059o from the center of the
pattern. What is the wavelength and color of the
light used?
l 0.5mm sin(0.059o) 5.15 10-7m 515nm
green
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35-6. Intensity in Double-Slit Interference
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35-6. Intensity in Double-Slit Interference
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35-6. Intensity in Double-Slit Interference
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35-6. Intensity in Double-Slit Interference
The screen is at distance D 4 m. The point P is
at distance y 20 cm from the center of the
pattern. The slits separation is 5 mm and the
wavelength is 600 nm. What is the ratio of the
intensity at point P to the intensity at the
center of the pattern?
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35-8. Michelson Interferometer
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35-8. Michelson Interferometer
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35-8. Michelson Interferometer
3000 km
Hanford, WA
h ?L/L 1021 L 4 km ?L 1018 m
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GEO600 (British-German) Hannover, Germany
TAMA (Japan) Mitaka
VIRGO (French-Italian), Cascina, Italy
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50 million km
5 million km
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36. Diffraction
Circular Aperture
Disk Fresnels Spot
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36-3. Single-Slit Diffraction

• Destructive Interference

Pair-wise Cancellation
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36-3. Single-Slit Diffraction

• Destructive Interference

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