1 | Page
Astronomy 101 Exam 2 Questions and
Correct Answers
Which of the following forms of light can be observed with
telescopes at sea level? Ans: visible light, radio waves
If our eyes were sensitive only to X rays, the world would appear
__________. Ans: dark because X-ray light does not reach Earth's
surface
If you had only one telescope and wanted to take both visible-light
and ultraviolet pictures of stars, where should you locate your
telescope? Ans: in space
Listed following are distinguishing characteristics and examples of
reflecting and refracting telescopes. Match these to the
appropriate category. Ans: Reflecting telescope: most commonly
used by astronomers today, worlds largest telescope, the hubble
space telescope
Refracting telescope: very large telescopes become top heavy, the
worlds largest is 1-meter in diameter, incoming light passes
through glass, Galileo's telescopes
Find the speed for a star in which this line appears at wavelength
120.4 nm
© 2025 All rights reserved
, 2 | Page
Find the direction for a star in which this line appears at
wavelength 120.4 nm . Ans: 2960 km/s
Towards us
Find the direction for a star in which this line appears at
wavelength 121.3 nm
Find the direction for a star in which this line appears at
wavelength 121.3 nm Ans: 740 km/s
Toward us
The Hubble Space Telescope obtains higher-resolution images than
most ground-based telescopes because it is: Ans: above earths
atmosphere
Suppose you watch a leaf bobbing up and down as ripples pass it
by in a pond. You notice that it does two full up and down bobs
each second. Which statement is true of the ripples on the pond?
Ans: They have a frequency of 2 hertz.
© 2025 All rights reserved
, 3 | Page
Which of the following best describes why we say that light is an
electromagnetic wave? Ans: The passage of a light wave can cause
electrically charged particles to move up and down.
Which of the following statements about X rays and radio waves is
not true? Ans: X rays travel through space faster than radio waves.
Each of the following describes an "Atom 1" and an "Atom 2." In
which case are the two atoms different isotopes of the same
element? Ans: Atom 1: nucleus with 7 protons and 8 neutrons,
surrounded by 7 electrons; Atom 2: nucleus with 7 protons and 7
neutrons, surrounded by 7 electrons
Which of the following statements is true of green grass? Ans: It
absorbs red light and reflects green light.
Which of the following conditions lead you to see an absorption
line spectrum from a cloud of gas in interstellar space? Ans: The
cloud is cool and lies between you and a hot star.
Which of the following statements about thermal radiation is
always true? Ans: A hot object emits more radiation per unit
surface area than a cool object.
Betelgeuse is the bright red star representing the left shoulder of
the constellation Orion. All the following statements about
Betelgeuse are true. Which one can you infer from its red color
Ans: Its surface is cooler than the surface of the Sun.
Laboratory measurements show hydrogen produces a spectral line
at a wavelength of 486.1 nanometers (nm). A particular star's
spectrum shows the same hydrogen line at a wavelength of 486.0
nm. What can we conclude? Ans: The star is moving toward us.
© 2025 All rights reserved
Astronomy 101 Exam 2 Questions and
Correct Answers
Which of the following forms of light can be observed with
telescopes at sea level? Ans: visible light, radio waves
If our eyes were sensitive only to X rays, the world would appear
__________. Ans: dark because X-ray light does not reach Earth's
surface
If you had only one telescope and wanted to take both visible-light
and ultraviolet pictures of stars, where should you locate your
telescope? Ans: in space
Listed following are distinguishing characteristics and examples of
reflecting and refracting telescopes. Match these to the
appropriate category. Ans: Reflecting telescope: most commonly
used by astronomers today, worlds largest telescope, the hubble
space telescope
Refracting telescope: very large telescopes become top heavy, the
worlds largest is 1-meter in diameter, incoming light passes
through glass, Galileo's telescopes
Find the speed for a star in which this line appears at wavelength
120.4 nm
© 2025 All rights reserved
, 2 | Page
Find the direction for a star in which this line appears at
wavelength 120.4 nm . Ans: 2960 km/s
Towards us
Find the direction for a star in which this line appears at
wavelength 121.3 nm
Find the direction for a star in which this line appears at
wavelength 121.3 nm Ans: 740 km/s
Toward us
The Hubble Space Telescope obtains higher-resolution images than
most ground-based telescopes because it is: Ans: above earths
atmosphere
Suppose you watch a leaf bobbing up and down as ripples pass it
by in a pond. You notice that it does two full up and down bobs
each second. Which statement is true of the ripples on the pond?
Ans: They have a frequency of 2 hertz.
© 2025 All rights reserved
, 3 | Page
Which of the following best describes why we say that light is an
electromagnetic wave? Ans: The passage of a light wave can cause
electrically charged particles to move up and down.
Which of the following statements about X rays and radio waves is
not true? Ans: X rays travel through space faster than radio waves.
Each of the following describes an "Atom 1" and an "Atom 2." In
which case are the two atoms different isotopes of the same
element? Ans: Atom 1: nucleus with 7 protons and 8 neutrons,
surrounded by 7 electrons; Atom 2: nucleus with 7 protons and 7
neutrons, surrounded by 7 electrons
Which of the following statements is true of green grass? Ans: It
absorbs red light and reflects green light.
Which of the following conditions lead you to see an absorption
line spectrum from a cloud of gas in interstellar space? Ans: The
cloud is cool and lies between you and a hot star.
Which of the following statements about thermal radiation is
always true? Ans: A hot object emits more radiation per unit
surface area than a cool object.
Betelgeuse is the bright red star representing the left shoulder of
the constellation Orion. All the following statements about
Betelgeuse are true. Which one can you infer from its red color
Ans: Its surface is cooler than the surface of the Sun.
Laboratory measurements show hydrogen produces a spectral line
at a wavelength of 486.1 nanometers (nm). A particular star's
spectrum shows the same hydrogen line at a wavelength of 486.0
nm. What can we conclude? Ans: The star is moving toward us.
© 2025 All rights reserved
