Physics Chapter 29
If the axes of a pair of Polaroids are parallel or at a ____ degree angle to each other then light _____ pass through them
45; will
How much ordinary light will an ideal Polaroid transmit?
50%
(AM/FM) radio waves diffract around buildings.
AM
Which more easily diffracts around buildings, AM or FM radio waves? Why?
AM waves, because the wavelengths are a hundred times longer than FM waves
Is interference restricted to only some types of waves or does it occur for all types of waves?
All types of waves
Constructive interference due to the superposition of identical waves causes a doubling of the wave's _______.
Amplitude. Frequency does not change and speed does not change.
According to Huygens, how does every point on a wavefront behave?
As a source of secondary wavelets
A double-slit arrangement produces interference fringes for yellow sodium light. To produce narrower-spaced fringes, should red light or blue light be used?
Blue light
When the reflected path from one surface of a thin film is one full wavelength different in length from the reflected path from the other surface and no phase change occurs, will the result be destructive interference or constructive interference?
Constructive interference.
When the reflected path from one surface of a thin film is one-half wavelength different in length from the reflected path from the other surface and no phase change occurs, will the result be destructive interference or constructive interference?
Destructive interference
Is diffraction more pronounced through a small opening or through a large opening?
Diffraction is more pronounced through a small opening, where small is compared to a wavelength.
True or False: Two waves cannot exist in the same place.
False
When is diffraction a hindrance and when is it helpful? (think large and small)
Helpful like in radio waves that bend around a building. A hindrance, like in a microscope when there's diffraction which makes the image blurry.
What type of sounds does a dolphin emit?
High frequency
_______ employ the principle of diffraction and _________ since there are simply a complex __________.
Holograms; interference; diffraction grating
How can a hologram be magnified?
If you view it with light that has a longer wavelength than the original.
What is the cause of Newton's rings?
Interference between light reflected from the top and bottom of an air gap when the curvature side of a convex lens rests on a flat glass
What accounts for the light and dark bands produced when monochromatic light reflects from a glass pane atop another glass pane?
Interference from the light reflected from the air - glass interfaces on the top and bottom of the air gap between the glass panes
What produces iridescence?
Interference of light waves
What causes the spectrum of colors seen in gasoline splotches on a wet street? Why are these not seen on a dry street?
It is caused by the interference of light waves reflected from the top of the gasoline layer and the bottom where the gasoline floats on water. They dry surface is rough and interference works best with a flat-topped layer of water.
Which can diffract more, long wavelengths or short ones?
Long wavelengths
For an opening of a given size, is diffraction more pronounced for a longer wavelength or for a shorter wavelength?
Longer wavelengths.
What type of wave is a sound wave?
Longitudinal wave
When ordinary light is incident at an oblique angle upon water, what can you say about the reflected light?
More of the reflected light is polarized horizontally.
According to Huygens' principle, every point on a wave behaves as a source for ________
New waves
What depth would be perceived if the images being projected in Figure 29.40 were identical? Why?
No depth could be perceived. The brain uses differences in two images to perceive differences in depth.
Can polarization occur with a sound wave? Ever?
No, only transverse. Never, it's longitudinal.
If you and your friend are looking at opposite sides of a soap bubble do you see the same color?
No.
What is meant by saying that a surface is optically flat?
Optically flat means that surface irregularities are small compared to the wavelength of light.
Polaroid filters appear dark when they are _________ to each other.
Perpendicular
What phenomenon distinguishes longitudinal waves from transverse waves?
Polarization
What role do polarization filters play in three-dimensional projection?
Polarizing filters allow the left-eye image to be seen only by the left eye, and the right-eye image to be seen only by the right eye.
A ______ opening though which waves fan out would produce more pronounced waves than a _____ opening.
Small; large
How does the direction of the polarization of light compare with the direction of vibration of the electron that produces it?
The direction of polarization is parallel to the direction of electron vibration.
How does a hologram differ from a conventional photograph?
The hologram appears to be three dimensional. you can look around objects in a hologram.
Will light pass through a pair of Polaroids when the axes are aligned? When the axes are at right angles to each other? Why?
The light that passes through the first Polaroid comes out completely polarized in the direction of the polarizer, so it easily passes through the analyzer with an aligned axis but not through one with an axis at right angles.
What aspect of light did Thomas Young demonstrate in his now famous light experiment?
The principle of superposition known as interference
Is parallax evident when you close one eye? Why?
The view through one stationary eye shows no parallax, because it takes two different views to see parallax.
Will plane waves incident upon a small opening in a barrier fan out on the other side or continue as place waves?
They will fan out and decrease in amplitude.
What type of wave is a light wave?
Transverse wave
Light illuminates two closely spaced thin slits and produces an interference pattern on a screen behind. For which color of light - yellow or green - will the distance between the fringes be greater?
Yellow
Does parallax underlie the depth perceived in stereo views?
Yes. Presenting two different views, one to each eye, mimics parallax and allows the brain to perceive three dimensions.
A pair of perpendicularly crossed Polaroids can transmit light only if:
You place a third Polaroid in the middle of the two at a 45 degree angle.
If a thin film appears yellow when illuminated with white light, then the color being cancelled ______.
blue
When waves from a pair of closely-spaced slits arrive in phase a _________ is produced.
bright fringe
When waves from a pair of closely-spaced slits arrive out of phase a ________ is produces
dark fringe
A ________ can separate light into its component colors.
diffraction grating
Diffraction can be reduced when illumination is with an _________
electron beam.
If a thin film appears magenta when illuminated with white light, then the color being cancelled is ______.
green
Glare seen from water or even the street is largely ________ polarized
horizontally
Iridescent colors in the soap bubbles, in thin films of gasoline on top of water and the inside of sea shells are due to _________.
interference
Light of a single frequency, wavelength and color is known as _________ light
monochromatic
Light emitted by a candle, a lamp or the Sun is ___________
non-polarized light
If a thin film appears cyan when illuminated with white light, then the color being cancelled is ______
red.
Huygens' principles to both waves of ________ and _________.
reflection; refraction
If a long-wavelength is seen in a soap bubble, then the wavelength being cancelled must be relatively _______
short
Diffraction can be observed when a wave passes through a ______ opening and the ____ of an object.
small; edge
Cancellation and reinforcement is produced by the __________ of waves
superposition
Interference colors in a soap bubble are evidence that the soap film is _____ and has ________ reflecting surfaces.
thin; 2 layers
The wave nature of light was finally proven with Thomas Young's ___________ demonstration
two source interference patterns
The polarization axes in sunglasses are ______
vertical
