AST 105: EXAM 1
62 Cards in this Set
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The Hα (Hydrogen-alpha) line has a wavelength of ______ and is in the ______ part of the spectrum.
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656 nm, red
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The Sun is composed mostly of.
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hydrogen and helium
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In the classroom demonstration using the infrared camera, what material did thermal infrared radiation pass through?
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air and the black plastic bag
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Comparing X-ray photons to microwave photons, we can say that X-ray photons have ______ energy, ______ frequency, and ______wavelength than do microwave photons.
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higher, higher, shorter
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10,000 km equals
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6000 miles
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In what wavelength range do humans at room temperature radiate energy most strongly?
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infrared
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An electromagnetic wave is ______ wave in which the oscillating electric and magnetic forces are ______ to the travel direction.
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transverse, perpendicular
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Which type of visible light photon has the lowest energy?
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orange
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What best describes the shape of a black body curve?
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the intensity is low at very long and very short wavelengths and has a broad peak at intermediate wavelengths
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What types of radiation do night vision goggles detect?
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infrared and visible
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A nanometer (nm) is equal to . .
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10^-9 m
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What effect does an electromagnetic wave have on electrons?
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it causes electrons to oscillate back and forth
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When a photon is emitted from an atom, this indicates that an electron moved to a ______ orbit which corresponds to a move to ______ energy level.
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smaller, a lower
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Which constellation contains Polaris, the North Star?
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Ursa Minor
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About how long does the Sun spend in each zodiacal constellation?
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1 month
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Suppose that ocean waves travel 4 meters per second. If the frequency is 2 waves per second, what is the wavelength of the waves?
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2 meters (use c = λv)
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For two stars with the following surface temperatures, calculate the ratio of wavelengths of peak emission λmax1/λmax2.
T1 = 3000 K, T2 = 9000 K
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3 (use λmax = cont./T)
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For a wave, the distance between successive crests is the ______ and the number of wave crests per time passing a point is the ______.
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wavelength, frequency
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A string of length L is stretched between two points and vibrated so that at any time the midpoint of the string remains at rest, one half of the string goes up, and the other half of the string goes down. In this case, the wavelength of the oscillation on the string is equal to:
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L
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The temperature in this room is closest to:
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290 K
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A professor shakes a spring stretched horizontally. As he slows down his shaking (fewer shakes per second) the wavelength of the waves:
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increases
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Jumps between level 2 and higher levels in the hydrogen atom are seen in the. . .
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visible
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For a black body, the temperature varies ______ with the ______ of the black body.
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inversely, wavelength of peak emission
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A star with a surface temperature higher than that of the Sun appears ______ because ______.
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blue, it emits more blue light than red light
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What is the brightest star in this constellation?
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Aldebaran
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If the mass of an electron is converted into a gamma ray, the wavelength of the gamma ray is 0.00000000000243 m. The correct way to express this in scientific notation is:
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2.43 x 10^-12
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As seen from Bloomington, the sky appears to rotate daily ______ about ______.
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counterclockwise, Polaris
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According to Kirchoff's Kaws, a low-density, cooler gas produces ______when viewed in front of a hotter continuous source.
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an absorption-line spectrum
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Which of the following statements about photons is correct?
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photons cannot be divided into smaller units
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Comparing black bodies of different temperature: 1) λmax ____ as temp. increases and 2) at any wavelength, a hotter black body has a ____ intensity.
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decreases, larger
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Which of the following has an emission-line spectrum?
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neon sign
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What order arranges wavelengths from short to long (high to low frequency)?
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gamma-ray, ultraviolet, visible, infrared radio
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Consider an ultraviolet photo of wavelength 250 nm and another ultraviolet photon of wavelength 25 nm. The ratio of photo energies E250/E25 is:
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1/10
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The two primary windows at which the Earth's atmosphere is transparent to electromagnetic radiation are:
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radio and optical
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A traditional incandescent light bulb produces a ______ spectrum. The spectrum is produced by a ______ inside the bulb.
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continuous, hot solid object
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The Sun is ______ times larger in diameter than the Earth.
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100
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What happens to a small element of water when a wave crosses a pond?
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It moves in a small circle that combines up/down and back/forth motion.
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A normal hydrogen atom contains ______ proton(s), ______ neutron(s), and ______ electron(s).
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1, 0, 1
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The Earth rotates on its axis from ______ making the celestial sphere appear to rotate from ______.
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west to east, east to west
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Which of the following properties is the same for all types of electromagnetic radiation in a vacuum?
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speed
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Which of the following is most responsible for different constellations becoming visible at different times of the year?
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the Earth's orbit about the Sun
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The Sun has a surface temperature of about 6000 K and a λmax value of 500 nm. A star with a surface temperature of 12,000 K will have a λmax value of ______.
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250 nm
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For photons 1 and 2, if v1/v2 = 4, find λ1/λ2.
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1/4
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What value is needed to directly find the surface temperature of the Sun?
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λmax of the Sun
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A measure of brightness at a particular wavelength is ______.
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intensity
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When an atom absorbs a sufficiently energetic photon to cause an electron to jump out of the atom, this is called:
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ionization
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Which type of photon behaves least like a particle?
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radio
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A traditional incandescent light bulb produces a ___ spectrum. The spectrum is produced by a ___ inside the bulb.
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continuous, hot solid object
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Which has an absorption-line spectrum: heated bar of iron, photosphere of the sun, or neon signs?
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Photosphere of the sun
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In a plot of a black body curve, the axes are:
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intensity and wavelength
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In the class demonstration in which a match was lighted, what type of radiation was used?
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infrared
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Which stars are a part of the summer triangle?
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Vega, Deneb, Altair
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As a frequency of a photon decreases, the photon energy ____. As the wavelength decreases, the photon energy ____.
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decreases, increases
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According to Kirchoff's laws, a hot, low-density gas produces:
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an emission-line spectrum
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Which wavelength region of the electromagnetic spectrum is taken up by visible light?
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400nm - 700nm
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A photon of which color has the highest energy?
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Violet
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An Astronomical Unit (AU) is equal to:
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The average distance of the Earth from the Sun
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1000 km =
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600 miles
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About how long does it take light to travel across the diameter of the Milky Way Galaxy?
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100,000 years
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A millimeter (mm) is equal to ____.
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10^-3 m
1mm = .001m
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In applying the scientific method to the study of our natural surroundings, scientists are:
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formulating hypotheses or models that describe the present observations of nature and that predict possible further tests for these models.
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A sound wave is an example of a ___ wave in which the oscillation is ___ to the travel direction.
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longitudinal, parallel
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AST 105: Final