Astronomy Light Quiz

Two stars are giving off electromagnetic radiation. The hotter star will: a) all of the above b) will radiate energy at more than one wavelength c) will give off a continuous spectrum of waves d) will have a higher average frequency of radiation e) give off more radiation at all wavelengths

a) all of the above

Why is an absorption spectrum especially useful for astronomers? a) It has dark lines in it that allow astronomers to determine what elements are in the star b) An absorption spectrum is not useful to astronomers at all. c) When they see one, it means they cannot learn anything about the stars that produced the annoying absorption. d) It helped astronomers to understand the rainbows we see on Earth after storms e) It has bright lines in it which allow astronomers to determine how bright the star is f) It shows that the stars are transparent; we can see right through them

a) it has dark lines in it that allow astronomers to determine what elements are in the star

We have two waves of light, A and B. Wave A has a higher frequency than wave B. Then wave B must have: a) longer wavelength b) lower speed c) shorter wavelength d) higher speed e) this can't be determined from the information given

a) longer wavelength

Astronomers observe a typical star using a telescope and a spectrometer. They will see: a) more than one of the above b) an absorption spectrum c) an emission spectrum d) a continuous spectrum e) a Doppler shift

a) more than one of the above

A fashion designer decides to bring out a new line of clothing which reflects the longest wavelength of visible light. What color will these articles of clothing be to the human eye? a) red b) yellow-green c) black d) violet e) blue

a) red

Wien's Law relates the wavelength at which a star gives off the greatest amount of energy to the star's a) temperature b) none of the above c) magnetic field d) overall color e) motion toward us or away from us

a) temperature

Which of the following statements about electromagnetic radiation is FALSE? a) the radiation consists of tiny charged particles given off by the nuclei of atoms b) it is given off by all objects that are not at a temperature of absolute zero c) it always spreads out at the speed of light d) different waves of electromagnetic radiation differ in their wavelength or frequency

a) the radiation consists of tiny charged particles given off by the nuclei of atoms

Which of the following has the longest wavelength? a) radio waves b) x-rays c) visible light waves d) you can't fool me, all these have the same wavelength e) ultraviolet waves

a) the radio waves

How fast do electro-magnetic waves travel? at the speed of sound a) at the speed of light b) at the speed of charge c) they always have zero speed d) at different speeds, depending on the temperature of the atoms that produce them

a) the speed of light

The fastest speed in the universe is: a) the speed of light b) the speed with which Mercury orbits the Sun c) the speed of sound d) the speed with which weekends seem to pass e) the speed of electron oscillations

a) the speed of light

(In the absence of a strong magnetic field), what is the chief factor that determines what type of electromagnetic radiation objects give off: a) their temperature b) their size c) their mass d) their chemical makeup e) their distance from the Earth's center

a) their temperature

An idealized object that does not reflect or scatter any radiation that hits it, but simply absorbs every bit of radiation that falls on it is called: a) an electromagnetic radiator b) a blackbody c) a doppler surface d) a spectrum

b) a blackbody

How do astronomers learn what elements are present in a given star? a) look at what color light dominates its continuous spectrum b) listen for coded signals in the radio waves it gives off in the FM band c) look at the absorption lines in its spectrum send spacecraft like Voyager to examine its make-up from close-up d) compare visible-light photographs of the star (taken with large telescopes) to those of the Sun.

b) look at the absorption lines in its spectrum send spacecraft like Voyager to examine its make-up from close-up

Two stars have the same diameter and are at the same distance from us (but in different parts of the sky.) Star A has a temperature of 4000 K, while star B has a temperature of 8000K. Which of the following statements is true: a) the two stars have the same total energy flux (luminosity) Correct! b) star B has 16 times the energy flux (luminosity) that star A has c) star B has one half the energy flux (luminosity) that star A has d) star B has twice the energy flux (luminosity) that star A has e) Sorry, professor, we don't have enough information to compare the energy flux (luminosity) of the two stars

b) star B has 16 times the energy glut (luminosity) that star A has

Most ultraviolet radiation does not penetrate to the Earth's surface. Instead it is absorbed in: a) the ionosphere b) the ozone layer c) stratosphere d) the region between the Earth and the Sun

b) the ozone layer

What happens as an electron falls from a higher level to a lower level in an atom? a) another electron from the lower level takes its place b) the color of the wave involved shifts to the red a photon is absorbed c) a photon is given off d) nothing happens; electrons can only go from a lower level to a higher level

c) a photon is given off

We discussed that light sometimes acts like a photon. What is a photon? a) you can't fool me. Einstein showed that photons were a mistake - they don't exist. b) a kind of magnetic substance found in reflective minerals c) a kind of sound that is too high frequency for the human ear to hear d) a self-contained "packet" of electro-magnetic energy e) a charged particle in the nucleus of every atom

c) a self-contained "packet" of electro-magnetic energy

To go from a lower level in an atom to a higher level, an electron must a) lose its electric charge b) give off a photon of energy c) absorb a photon of energy d) wait until the atom has changed into another atom with more protons

c) absorb a photon of energy

The fact that each type of atom has a unique pattern of electron orbits helps explain why a) most atoms don't have a ground state b) some atoms don't have any isotopes c) each type of atom shows different absorption or emission spectra d) astronomers have not been able to figure out what atoms stars are made of e) each type of atom contains different numbers of neutrons

c) each type of atom shows different absorption or emission spectra

Which of the following has the highest frequency? a) you can't fool me, all these have the same frequency b) visible light c) gamma rays d) radio waves e) ultraviolet waves

c) gamma rays

You are alone in a large, completely dark auditorium on Earth. What kind of telescope should I use from the other side of the auditorium to detect the electromagnetic radiation emitted by your body? a) black light b) visible light c) infra-red d) ultra-violet e) no telescope will be effective if I am in a dark room

c) infrared

Which of the following statements about photons is FALSE? a) high energy photons have a high frequency (when thought of as waves) b) a gamma-ray photon carries more energy than a visible light photon c) Answer photon of visible light cannot pass through the atmosphere of the Earth, and thus cannot be seen at the Earth's surface d) photons each carry a specific amount of energy e) photons always travel at the speed of light

c) photon of visible light cannot pass through the atmosphere of the Earth, and thus cannot be seen at the Earth's surface

I want to examine the surface of a planet that is covered by a thick atmosphere (which includes oxygen and contains a very thick layer of water clouds that never clears). What wavelength of electromagnetic radiation would I be smartest to use: a) x-rays b) ultra-violet c) Answer radar waves d) You Answered visible light e) none would work

c) radar waves

Not all wavelengths of electromagnetic radiation can penetrate the Earth's atmosphere. Of the following types of waves that come from space, which one are you likely to be able to detect most easily from our planet's surface: a) infrared waves b) ultraviolet waves c) radio waves of the wavelength that carry FM broadcasts d) x-rays e) gamma rays

c) radio waves of the wavelength that carry FM broadcasts

A Hertz is: a) a unit of loudness b) a unit of wavelength c) a unit of velocity d) a unit of frequency

d) a unit of frequency

An artist who likes working with sources of light decides to make a modern sculpture out of electrified glass tubes that contain very thin (rarified) neon gas. When the sculpture is finished, and the electricity is turned on, the tubes glow with a rich red color. What we are seeing is: a) an absorption spectrum b) all of the above c) a continuous spectrum d) an emission spectrum e) a Doppler shift

d) an emission spectrum

An astronomer discovers a new star and wants to measure its temperature. She would typically do this by: a) measuring how much light the star reflects b) sending a graduate student with a very long (and durable) thermometer to the star's vicinity c) measuring the Doppler shift of its spectral lines d) making a blackbody curve and finding the wavelength of the peak (maximum) e) measuring the intensity of radio waves the star gives off

d) making a blackbody curve and finding the wavelength of the peak (maximum)

When a star or galaxy is moving away from us, we observe the Doppler effect by seeing the lines in its spectrum a) you can't fool me, the Doppler effect only applies to motions on Earth, not to the motions of the stars and galaxies b) yellow-shifted (shifted so all the colors become a little bit yellower) c) become darker and darker (like a blackbody) Correct! d) red-shifted (shifted toward the red end of the light spectrum) e) blue-shifted (shifted toward the blue or violet end of the light spectrum)

d) red-shifted (shifted toward the red end of the light spectrum)

We observe a glowing cloud of gas in space with a spectroscope. We note that many of the familiar lines of hydrogen that we know on Earth seem to be in a different place. They are shifted toward the blue or violet end of the spectrum compared to their positions in the spectrum of glowing hydrogen gas on Earth. From this we can conclude that: a) none of the above can be concluded from this observation b) the cloud is much hotter than hydrogen on Earth c) the cloud is much cooler than hydrogen on Earth d) the cloud is moving toward us e) the cloud is moving away from us

d) the cloud is moving toward us

The light which allows you to see this very interesting exam is made up of waves. In these waves, the distance between crests is called the: a) you can't fool me; in these waves, the distance between crests is zero b) frequency c) velocity d) wavelength e) amplitude

d) wavelength

An astronomer observes two ordinary stars. The first one turns out to be twice as hot as the second. This means that the first one radiates: a) this problem cannot be solved with just the information we were given b) half as much energy as the second c) roughly the same amount of energy as the second d) twice as much energy as the second e) about 16 times the energy of the second

e) about 16 times the energy of the second

Why do different types of atoms (elements) give off or absorb different spectral lines? a) because some atoms do not have a ground state, while others have three or four b) in some elements, electrons can only move to odd numbered levels, in others only to even numbered ones c) in heavier elements, diffraction spreads out the lines that the atom produces, making the colors different d) all elements have the same lines, but they are Doppler shifted by different amounts e) because the spacing of the energy levels is different in different atoms

e) because the spacing of the energy levels is different in different atoms

The Stefan-Boltzmann Law relates the energy flux coming from a blackbody (such as a star) to its: a) overall color b) atomic ground state c) none of the above d) wavelength where maximum energy is emitted e) temperature

e) temperature

In the future, several students living on board a space station decide to have a race among different types of electromagnetic radiation. Which of the following travels through space the fastest? a) radio waves b) x-rays c) infrared d) visible light e) you can't fool me, all of these travel through space at the same speed

e) you can't fool me, all of these travel through space at the same speed

The energy of random atomic and molecular motion is called a) the doppler shift b) heat c) reflection d) spectra

heat