Two coherent light sources. Q35.1. Two sources S 1 and S 2 oscillating in phase emit sinusoidal waves. Point P is 7.3 wavelengths from source S 1 and 4.3 wavelengths from source S 2 . As a result, at point P there is. A. constructive interference. B. destructive interference. - PowerPoint PPT Presentation
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Interference from two radio stations revisited• Radio station operating at 1500 kHz has two antennas spaced
400m apart. In which directions is the intensity greatest in the resulting radiation pattern far away (>> 400m) from the antennas? How many total regions of high intensity are there?
Coherent light passing through two slits (S1 and S2) produces a pattern of dark and bright areas on a distant screen. If the wavelength of the light is increased, how does the pattern change?
Q35.3
A. The bright areas move closer together.
B. The bright areas move farther apart.
C. The spacing between bright areas remains the same, but the color changes.
Coherent light passing through two slits (S1 and S2) produces a pattern of dark and bright areas on a distant screen. If the wavelength of the light is increased, how does the pattern change?
A35.3
A. The bright areas move closer together.
B. The bright areas move farther apart.
C. The spacing between bright areas remains the same, but the color changes.
Diffraction gratingWhat is the first order diffraction peak (angle) for a grating with 600 slits per mm for red (700 nm) and violet (400nm) light? For a screen 1 m away, what distance away from the central peak is the first order peak?
By what angle (max angle minus min angle) is the rainbow spread out for the first order diffraction?
How many constructive interference peaks are there?
Fraunhofer diffraction and an example of analysis• A red laser (700nm) is shown through a single slit.• What is the slit width for this diffraction pattern?
In a single-slit diffraction experiment with waves of wavelength l, there will be no intensity minima (that is, no dark fringes) if the slit width is small enough.
What is the maximum slit width a for which this occurs?
Q36.2
A. a = l/2
B. a = l
C. a = 2l
D. The answer depends on the distance from the slit to the screen on which the diffraction pattern is viewed.
In a single-slit diffraction experiment with waves of wavelength l, there will be no intensity minima (that is, no dark fringes) if the slit width is small enough.
What is the maximum slit width a for which this occurs?
A36.2
A. a = l/2
B. a = l
C. a = 2l
D. The answer depends on the distance from the slit to the screen on which the diffraction pattern is viewed.
In Young’s experiment, coherent light passing through two slits separated by a distance d produces a pattern of dark and bright areas on a distant screen.
If instead you use 10 slits, each the same distance d from its neighbor, how does the pattern change?
Q36.3
A. The bright areas move farther apart.
B. The bright areas move closer together.
C. The spacing between bright areas remains the same, but the bright areas become narrower.
D. The spacing between bright areas remains the same, but the bright areas become broader.
In Young’s experiment, coherent light passing through two slits separated by a distance d produces a pattern of dark and bright areas on a distant screen.
If instead you use 10 slits, each the same distance d from its neighbor, how does the pattern change?
A36.3
A. The bright areas move farther apart.
B. The bright areas move closer together.
C. The spacing between bright areas remains the same, but the bright areas become narrower.
D. The spacing between bright areas remains the same, but the bright areas become broader.
Michelson and Morley’s interferometer• In this amazing experiment at Case Western Reserve, Michelson and Morley
suspended their interferometer on a huge slab of sandstone on a pool of mercury (very stable, easily moved). As they rotated the slab, movement of the earth could have added in one direction and subtracted in another, changing interference fringes each time the device was turned a different direction. They did not change. This was an early proof of the invariance of the speed of light.