ASTR 121 JMU Test One 169 Quiz Questions Final End Of Sem Correctly Answered
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Course
ASTR 121 JMU
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ASTR 121 JMU
(In the absence of a strong magnetic field), what is the chief factor that determines what type of electromagnetic radiation objects give off: - ️️their temperature
A college friend of yours who has been postponing taking any science courses hears you talking about the generation of nuclear en...
(In the absence of a strong magnetic field), what is the chief factor that determines what type of
electromagnetic radiation objects give off: - ✔ ✔ their temperature
A college friend of yours who has been postponing taking any science courses hears you talking about
the generation of nuclear energy in the Sun and makes the following observation: "The whole idea of
the atomic nucleus is pretty ridiculous. If an oxygen nucleus consists of eight protons and eight
neutrons, the charge on that nucleus is positive. Since even I learned in high school that like charges
repel, such a nucleus would find all its positive protons repelling and quickly fall apart." How would you
answer his argument? - ✔ ✔ the strong nuclear force, which is attractive over short distances like
the nucleus, and stronger than electricity, holds the nucleus together
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? - ✔ ✔ red
A friend of yours who has not taken an astronomy class looks at your textbook and really likes the
picture of the Pleiades, a cluster of stars surrounded by a bluish reflection nebula. She wants to know
what causes that beautiful blue glow. To explain it to her, you want to compare the process that causes
the blue glow to something that is in your friend's everyday experience. Which of the following
terrestrial phenomena is the result of the same type of process that makes a reflection nebula in space?
- ✔ ✔ the blue color of the Earth's sky
A graduate student has done a careful analysis of the spectrum of a star. While she has found lines from
many elements, there was not a trace of the element helium in the spectra she has been analyzing.
From this she can now conclude: - ✔ ✔ since helium shows lines only in hot stars, this star must be
relatively cool
A Herbig-Haro (HH) object is - ✔ ✔ where a jet from a star in the process of being born collides with
(and lights up) a nearby cloud of interstellar matter
A Hertz is - ✔ ✔ a unit of frequency
A star moving toward the Sun will show: - ✔ ✔ a shift in the spectral lines toward the blue end (as
compared to the laboratory positions of these lines)
A star that is quite hot and has a very small radius compared to most stars is called - ✔ ✔ a white
dwarf
, A star whose temperature is increasing but whose luminosity is roughly constant moves in what
direction on the H-R diagram? - ✔ ✔ to the left
A team of astronomers takes spectra of thousands of different stars in different parts of the sky. The
spectra show significant differences. The main reason the spectra of the stars do not all look alike is that
the stars - ✔ ✔ are made of significantly different elements
A white dwarf, compared to a main sequence star with the same mass, would always be: - ✔ ✔
smaller in diameter
According to the formula E=mc2 - ✔ ✔ a little bit of mass can be converted into a substantial amount
of energy
After a lot of work, a group of graduate students has finally measured the wavelengths of many dozens
of lines in the spectrum of a distant star. If a number of the lines come from molecules such as titanium
oxide, the star is likely to be which spectral type: - ✔ ✔ M
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: - ✔ ✔ an emission
spectrum
An astronomer discovers a new star and wants to measure its temperature. She would typically do this
by: - ✔ ✔ making a blackbody curve and finding the wavelength of the peak (maximum)
An astronomer is observing a star which puzzles her. The lines in the star's spectrum indicates that the
star is very hot and should therefore be blue. But the star looks reddish in photographs and in
measurements of the continuous spectrum. What is one possible explanation of this puzzle? - ✔ ✔
we are seeing the light of the star through layers of interstellar dust
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: - ✔ ✔ about 16 times the energy of the second
An astronomer wants to observe a cloud of cold neutral (not ionized) hydrogen, far away from any stars.
What would be an instrument that could help in this task? - ✔ ✔ a radio telescope, tuned to a
wavelength of about 21 centimeters
An astronomer wants to observe a cloud of dust in a relatively close part of the Galaxy. Unfortunately,
this dust cloud is not located in the direction of a crowded region of stars. What instrument would be
the most help in finding this cloud. - ✔ ✔ a sensitive infra-red telescope in orbit around the Earth
An astronomer whose secret hobby is riding merry-go-rounds has dedicated his career to finding the
stars that rotate the most rapidly. But the stars are all very far away, so none of them can be seen to
spin even when he looks through the largest telescopes. How then can he identify the stars that rotate
rapidly? - ✔ ✔ stars that rotate have much wider lines in their spectra than stars that do not
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