Astronomy 1020 Stellar Astronomy Sample Questions for Exam 1

Chapters 1

1.         A scientific hypothesis is

a)    a wild, baseless guess about how something works.

b)    a collection of ideas that seems to explain a phenomenon.

c)    an absolutely unbreakable law of physics.

d)    a first guess about what causes a physical phenomenon.

 

2.         In science, the final arbiter on whether a theory is correct is

a)    a committee of distinguished scientists.

b)    the Nobel committee in Stockholm Sweden.

c)    Nature.

d)    the scientist most responsible for developing the theory.

 

3.         The number 0.000000000025, written in scientific notation, is

a)   2.5x10^-11

b)   25x10^-11

c)    2.5x10¹¹

d)   25x10¹¹

e)   None of the above.

 

4.         The language of science is

a)    Greek.

b)    Latin.

c)    mathematics.

d)    English.

e)    None of the above, science has no language.

 

5.         Which of the following events did not occur in the last 60 years?

a)    Man first walked on the moon.

b)    The first orbital spacecraft was launched.

c)    The first space probes to the outer planets were launched.

d)    The first interstellar space probe reached the nearest star.

e)    All of the above occurred in the last 50 years.

 

6.         The light travel time to the nearest star other than our sun is measured in

a)    seconds.

b)    hours.

c)    days.

d)    years.

e)    None of the above, light travels instantaneously.

 

7.         Almost all the atoms in your body

a)    are primordial and have existed since the beginning of time.

b)    were created in the cores of stars that died billions of years ago.

c)    were created in our sun.

d)    were created in the center of the Earth and brought to the surface by volcanoes.

 

8.         The science of astronomy began with

a)    observations of the patterns of the stars at the beginning of recorded history.

b)    the construction of the first telescope in the 1600’s.

c)    the Greek astronomer Ptolemy.

d)    ancient Babylonians.

 

9.         The Cosmological Principle is

a)    There is nothing special or unique about the Earth.

b)    Observers on the Earth are special and only we see the universe as it really is.

c)    Observers on the Earth see a different universe than observers in other galaxies.

d)    The Universe is infinite.

 

Short Answer Questions

1.    Describe what is meant by “light travel time”. Give the light travel time to a number of celestial objects and discuss how it relates to their distance from Earth.

2.    Describe the scientific method and how scientists use it to explain physical phenomena.

3.    Why is it that most astronomers believe we are living in the “Age of Exploration” for astronomy? What are some of the explorations that have taken place in the last 50 years?

 

 

Chapter 2

1.         The 88 official constellations used today can be traced to

a)   every ancient culture around the world.

b)   European culture from 2000 years ago for northern constellations and 500 years ago for southern ones.

c)    ancient Chinese culture for the northern constellations and Australian aboriginal culture for southern ones.

d)   North American Indian culture for northern constellations and ancient South America cultures for southern ones.

e)   None of the above.

 

2.         The daily motions observed in the sky are due to

a)    the rotation of the Earth about its polar axis.

b)    the rotation of the celestial sphere about the celestial poles.

c)    the orbit of the Earth around the sun.

d)    the motion of the sun around the center of the Milky Way.

 

3.         We see different constellations during the different seasons

a)    because the stars are continually dying and new stars are being born.

b)    because the celestial sphere slowly rotates around the Earth.

c)    because the Earth orbits around the sun and we can only see the constellations that are on the opposite side from the sun.

d)    because of the rotation of the Earth about its polar axis.

 

4.         The celestial equator is

a)    the path the sun follows around the celestial sphere.

b)    the projection of the plane of the earth’s equator onto the celestial sphere.

c)    the projection of the line connecting the poles of the earth onto the celestial sphere.

d)    the circle around the celestial sphere formed by the Milky Way.

 

5.         The celestial poles are

a)    the path the sun follows around the celestial sphere.

b)    the projection of the line connecting the poles of the earth onto the celestial sphere.

c)    the projection of the plane of the earth’s equator onto the celestial sphere.

d)    the circle around the celestial sphere formed by the Milky Way.

 

6.         Circumpolar constellations are constellations that

a)   rise in the east an set in the west daily.

b)   never set, just circle the celestial pole.

c)    rise in the west and set in the east daily.

d)   rise in the south and set in the north annually.

 

Short Answer Questions

1.            Describe the origins of the constellations and their modern day definition.

2.            Using the celestial sphere model, describe motions of the stars. Be sure to make reference to the important reference marks of the celestial sphere.

 

 

Chapter 3

1.         Copernicus proposed that

a)   the Earth was at the center of the solar system.

b)   the Sun was at the center of the solar system.

c)    there was no center to the solar system.

 

2.         Tycho Brahe is best known for

a)   his close cooperation and friendship with Johannes Kepler.

b)   his invention of the telescope.

c)    his continuous, detailed and accurate observations of the planets and stars.

d)   his theoretical model of the universe.

 

3.         Which of the following is not one of Kepler’s laws of planetary motion?

a)   the Sun is at the center of the universe.

b)   the square of a planets orbital period is proportional to the cube of the planets average distance from the sun.

c)    the planets move on ellipses with the Sun located at one focus.

d)   a line drawn from a planet to the Sun will sweep out equal areas in equal time periods.

 

4.         In addition to his astronomical observations, Galileo Galilei is known for

a)   his close cooperation with and strong support for the Roman Catholic Church.

b)   his development of “new” physics to replace the old incorrect physics of Aristotle.

c)    his invention of the reflecting telescope.

d)   his close friendship and cooperation with Tycho Brahe.

 

5.         Which of the following is not one of Newton’s three laws of motion?

a)   For every force there is an equal and opposite reaction force.

b)   A line drawn from a planet to the sun will sweep out equal areas in equal time periods.

c)    The rate of change in the velocity of a body is directly proportional to the net force on the body and inversely proportional to the mass of the body.

d)   A body at rest or in motion at constant velocity will remain in that state unless acted on by some net external force.

 

6.         Which of the following is not a possible orbit of one body around another?

a)    A parabola

b)    An ellipse

c)    A hyperbola

d)    A straight line

 

7.         The Universal Law of Gravitation says that every particle of matter in the universe attracts every other particle with a force that varies

a)   directly with the sum of their masses and inversely with the distance between them.

b)   directly with the product of their masses and inversely with the distance between them.

c)    directly with the sum of their masses and inversely with the square of the distance between them.

d)   directly with the product of their masses and inversely with the square of the distance between them.

 

Short Answer Questions

1.            State Kepler’s Laws of Planetary Motion and the consequences and meaning of those laws.

2.            Describe an ellipse. Include a diagram with the major parts of the ellipse labeled and defined.

3.            State Newton’s Three Laws of motion.

4.            State Newton’s Universal Law of Gravitation and describe each of the terms in it and some of the consequences of the law.

 

 

Chapter 4

1.         “Light” is

a)    always a wave and never anything else.

b)    always a particle and never anything else.

c)    a disturbance that travels through the luminiferous aether.

d)    electromagnetic radiation.

 

2.         The electromagnetic spectrum is

a)    part of a refracting telescope.

b)    the entire range of “light” from gamma rays to very long radio waves.

c)    visible light.

d)    “light” that is not visible to the human eye.

 

3.         The speed of light

a)    depends on the relative speed between the source and the observer.

b)    is different for different wavelengths.

c)    is dependent on the intensity of the light.

d)    is 299792458 ^m/_s for all observers regardless of their speed.

e)    None of the above, light is instantaneous.

 

4.         One of the basic principles of Einstein’s Special Relativity is

a)    The speed of light depends on the relative speed between the source and the observer.

b)    It is always possible determine who is moving and who is stationary.

c)    The observed laws of physics are the same regardless of any constant velocity at which you move.

d)    It is possible to move at speeds greater than the speed of light.

e)    All of the above.

 

5.         If an observer is stationary on the surface of the Earth and watches a spacecraft moving past at ⁹/₁₀ the speed of light he sees

a)    simultaneous flashes on the spacecraft appear simultaneous to both him and the person on the spacecraft

b)    the stationary observer sees the moving clock as running fast.

c)    the stationary observer sees the moving length as long.

d)    the stationary observer sees the moving clock as running slow.

e)    None of the above, everything is the same.

 

6.         The modern model of the atom is

a)   a solid mass with no internal structure.

b)   a small nucleus composed of neutrons and protons surrounded by a cloud of electrons.

c)    a small nucleus composed of electrons and protons surrounded by a cloud of neutrons.

d)   a small sphere composed of electrons, protons and neutrons.

 

7.         Atoms emit light when

a)   an electron spontaneously falls from a high energy state to a lower energy state.

b)   an electron spontaneously jumps from a low energy state to a high energy state.

c)    an electron completes one orbit around the nucleus.

d)   an electron is thrown out of the nucleus.

 

8.         An energy level diagram is

a)    a diagram of the energy production process in the sun.

b)    a diagram of the energy released when an atom is split.

c)    a diagram of the possible energies that an electron can have in an atom.

d)    a diagram showing the physical position of the electron as it orbits around the nucleus.

e)    None of the above.

 

9.         Blackbody radiation is

a)    the individual wavelengths of light emitted from black holes.

b)    the individual wavelengths of light that are absorbed by objects that are painted black.

c)    the continuous spectrum of light that is emitted from objects due to their temperature.

d)    the individual wavelengths of light that are emitted from objects due to their elemental composition.

e)    None of the above.

 

10.       Which of the following is not a property of blackbody radiation?

a)    The blackbody spectrum is a continuous spectrum of light.

b)    The wavelength of maximum intensity decreases with increasing temperature.

c)    The total energy emitted increases with increasing temperature.

d)    All wavelengths are emitted with equal intensity.

 

11.       The spectrum of the sun is

a)    a blackbody spectrum of the 5800° surface with emission lines from all the elements.

b)    a blackbody spectrum of the 5800° surface with absorption lines from all the elements.

c)    a hydrogen emission spectrum.

d)    an emission spectrum of hydrogen, helium and most of the other elements.

e)    None of the above, the sun doesn’t have a spectrum.

 

12.       The Doppler effect is

a)    the change in observed wavelength of a wave when the source is moving with respect to the observer.

b)    the change in the observed intensity of a wave when the source is moving with respect to the observer.

c)    the change in the observed speed of light when the source is moving with respect to the observer.

d)    the change in the observed position of a star due to the relative motion of the earth around the sun.

e)    None of the above.

 

13.       If a light source is moving towards you the light will be

a)    redshifted.

b)    blueshifted.

c)    unchanged.

d)    converted into mass.

e)    None of the above.

 

Short Answer Questions

1.            Describe a “blackbody” spectrum and how its shape and size depends on the temperature of the object producing it. Make a graph illustrating the blackbody spectra of several ideal blackbodies at different temperatures.

2.            Describe the modern model of the atom. Include descriptions of how the mass and charge are distributed, the composition of the nucleus, electron energy levels and the location of the electrons.

3.            Briefly discuss Einstein’s Special Theory of Relativity. What are the basic assumptions of the theory? What are some of the consequences of the theory on objects that are moving at speeds close to the speed of light?

4.            Describe the Doppler Effect and give at least two ways that it can affect the spectrum of a star.