What is the ultimate source of electromagnetic waves?
Vibrating charged particles
If an electron vibrates up and down 1000 times each second, it generates an electromagnetic wave having a
speed of 1000 m/s.
wavelength of 1000 m.
period of 1000 s.
frequency of 1000 Hz.
Compared to the velocity of radio waves, the velocity of visible light waves is
The main difference between a radio wave and a light wave is its
speed and wavelength.
none of the above.
Compared to its speed in air, the speed of light in water is
Which of the following are fundamentally different from the others?
Which of these electromagnetic waves has the shortest wavelength?
If the sun were to disappear right now, we wouldn't know about it for 8 minutes because it takes 8 minutes
for light to travel from the sun to Earth.
to operate receiving equipment in the dark.
for the sun to disappear.
all of the above.
After randomly polarized light passes through a polarizer, it is
The source of all electromagnetic waves is
block UV light.
neither block nor transmit UV light.
transmit UV light.
Light that reflects at glancing angles from nonmetallic surfaces, such as glass, water, or roads is
polarized parallel to the surface.
polarized perpendicular to the surface.
Light does not pass through what kind of materials?
Neither transparent nor opaque
Solar eclipses are seen less commonly than lunar eclipses because
the sun is so much larger than the moon.
the sun is farther from Earth than is the moon.
Earth's shadow on the moon is larger than the moon's shadow on Earth.
solar eclipses don't happen as often as lunar eclipses.
How far is a light-second?
If two polarizing filters are held with their polarization axes at right angles to each other, the amount of light transmitted compared to when their axes are parallel is
twice as much.
half as much.
The shiny surfaces of metals have most to do with
a resonant frequency of electrons in the metal.
the fact that light reflects from metals.
metals; relatively high density.
the free electrons in metal atoms.
Electromagnetic waves are
Glass is transparent to visible light, but not to
infrared and ultraviolet.
Compared to the wavelength of ultraviolet waves, the wavelength of infrared waves is
Heat lamps give off mostly
Electromagnetic waves with higher frequencies have wavelengths that are
An ideal polarizing filter will transmit 50% of non-polarized light incident on it. How much light is transmitted by two ideal polarizing filters that are oriented with their axes parallel to each other?
Between 50% and 100%
Between 0% and 50%
can travel through a vacuum.
need a medium to travel through.
Light reflected from a lake surface is polarized
Which of the following is NOT an electromagnetic wave?
What is the frequency of an electromagnetic wave having a wavelength of 300,00 km?
Less than 1 Hz
More than 1 Hz
What is the wavelength of an electromagnetic wave that has a frequency of 1 Hz?
Less than 1 m
More than 1 m
The primary purpose of polarized sunglasses is
to block ultraviolet rays.
to block infrared rays.
to block glare from reflections.
to look cool.
Because of absorption, a polarizing filter will actually transmit 40% of incident non-polarized light. Two polarizing filters with their axes aligned will transmit
between 0% and 40%.
between 40% and 100%.
Infrared waves are responsible for sunburn.
A thin beam of light is called an X-ray.
Glass transmits ultraviolet and visible light waves but not infrared waves.
The distance light travels in one year is called light-year.
Materials that allow light to pass through them in straight lines are called opaque materials.
Polarization occurs when waves vibrate in a single direction.
Energy emitted by vibrating electric charges is carried by electromagnetic waves.
A total shadow is called an umbra.
Light sometimes acts as a wave and sometimes as a particle.
According to Einstein, light consists of massless bundles of electromagnetic energy called photons.
Electromagnetic heat waves are called ultraviolet waves.
The color of an object we see is determined by the
colors of light reflected by the object.
frequencies of light absorbed by the object.
colors of light shining on the object.
frequencies of light reflected by the object.
Sunlight contains all colors of light, but much of it is
Light shines on a pane of green glass and a pane of clear glass. The temperature will be
higher in the clear glass.
higher in the green glass.
the same in each.
Colors seen on TV result from color
Different colors of light correspond to different light
none of the above
When blue and yellow paints are mixed together, the result is green. The reason for this is that
blue and yellow are complementary colors.
yellow pigments absorb green light and reflect all the others.
blue reflects only blue light, and yellow reflects almost all colors of light.
between blue and yellow pigments, all colors are absorbed except green.
blue absorbs yellow light and yellow absorbs blue light.
Magenta light is really a mixture of
red and yellow light.
red and cyan light.
yellow and green light.
red and blue light.
The color of an opaque object is determined by the light that is
all of the above
If sunlight were green instead of white, the most comfortable color to wear on a hot day would be
If molecules in the sky scattered orange light instead blue light, sunsets would be colored
If the atmosphere were 50 times thicker than it now is, the sun would appear
The reason the sky is blue is that air molecules
reflect blue light.
absorb yellow light.
absorb and then reemit blue light, scattering it in all directions.
absorb green light.
Sunsets are red because
the longest path of sunlight through the atmosphere is at sunset or sunrise.
a lot of high-frequency light is scattered by the atmosphere.
blue light from the sun is scattered by Earth's atmosphere.
The true color of water is
The cyan color of ocean water is evidence that the water absorbs
When a sample of an element is heated until it glows, the color it gives off is
a continuous band of color.
a composite of many frequencies of light.
a single frequency of light.
The colors of light emitted by incandescent gases show the
absorbing qualities of gas.
polarization of atoms in the gas.
relative masses of atoms in the gas.
identities of atoms in the gas.
The three primary colors of light for additive color mixing are
red, green, and blue.
yellow, green, and blue.
red, yellow, and blue.
red, yellow, and green.
yellow, cyan, and red.
When red and green light shine on a white sheet, the resulting color is
The complementary color of blue is
The colored dots that make up the color on a TV screen are
red, blue, and yellow.
red, blue, and green.
magenta, cyan, and yellow.
red, green, and yellow.
yellow, blue, and green.
Spectral lines in a line spectrum take the shape of lines because the
atoms that emit the light vibrate along parallel lines.
light emitted aligns with the gravitational field.
slit of the spectroscope is itself a line opening.
light is polarized.
A photograph of your favorite person's yellow sweater shows as what color on the negative?
Material in an object that selectively absorbs colored light is called a pigment.
Two colors of light that add together to form black light are complementary colors.
A spectroscope is an instrument that analyzes the colors in a light beam.
Some electrons in atoms vibrate at a characteristic frequency that produces white light.
If an object were completely black, you wouldn't be able to see it directly.
If you're looking for an instrument that tells what stars are made of, look for a
The complementary color of green is
A sheet of red paper will look black when illuminated with
The white caps of waves as they overturn are evidence that the water has
broken into an assortment of tiny particles that scatter all colors.
lost its transparency.
reflected red, green, and blue light.
Humans are most sensitive to light that is
A tennis ball is most easily seen if its color is
Earth receives a lot of ultraviolet radiation from the sun. Luckily most of it does't reach the ground, because it is
scattered by the upper atmosphere.
absorbed by a protective layer of ozone gas in the upper atmosphere.
absorbed by the large amount of air in the atmosphere.
Actually, there isn't enough UV radiation coming from the sun to harm us.
The sky is blue because air molecules in the sky act as tiny
resonators that scatter blue light.
mirrors that reflect only blue light.
sources of white light.
The three paint colors that are useful for color subtraction are
magenta, cyan, and red.
magenta, green, and yellow.
Complementary colors are two colors that
are next to each other on the color chart.
produce white light when added together.
look good together.
are primary colors.
The sky is blue because air molecules absorb blue light.
Tennis balls are yellow-green because our eyes are most sensitive to that color.