Glossary of Physics 127
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- If a telescope with an objective lens of 10-foot focal length is used with an eyepiece of 1/4 inch focal length, the resulting magnification will be...
- You are on a strange planet. You note that the stars do not rise and set, but circle around parallel to the horizon. Then you travel over the surface of the planet in a straight line for 4500 miles and find that at this new place the stars rise straight
- 18,000 miles
- Orange light is of ______ than violet light.
- lower frequence and longer wavelength
- The horns of the crescent moon ALWAYS point...
- away from the Sun.
- At new moon the Earth would appear to an observer on the moon to be at _____ phase.
- When Venus has an elongation that is 20 degrees westward from the Sun, it is then visible...
- as a morning star
- What happens in our model of the atom when an emission line is formed?
- An electron moves from a higher energy level to a lower one.
- You live at 40 degrees north latitude. How often is the Sun directly overhead at noon in your hometown?
- The orbit of the Earth about the Sun defines a plane in space. The orbital plane between the Earth and the Sun is referred to as the...
- Although the stellar constellations are of very ancient origin, they are still useful to modern astronomers...
- for indentifying stars and designating locations on the sky.
- The first person known to suggest the heliocentric model for the solar system
- Wrote a series of books called the Almagest in which the epicycle theory of the solar system is described in great detail.
- Discovered the three laws of planetary motion
- Compiled the most accurate set of naked eye positional observations of the planets that had ever been made up to his time (1600 AD)
- Tycho Brahe
- Made a remarkably good estimate of the circumference of the Earth during the second century BC
- Used the orbits and eclipses of the moons of Jupiter to estimate the speed of light
- First used a telescope to observe the heavens in 1610
- Discovered the four large moons of Jupiter by direct observation
- Wrote the book De Revolutionibus Orbium Coelestium published in 1543
- Formulated the law of gravitation, the laws of motion and the nature of light
- constellation with the bright star...
- Ursa Minor
- Canis Minor
- Canis Major
- The second most abundant element in the Sun
- The planet that rotates on its axis with a period almost identical to that of the Earth is
- Stars at the upper left-hand end of the main sequence have which of these:
- large mass
- Which kind of process, as a net result, supplies the energy of our Sun?
- Hydrogen atoms are converted to helium through fusion.
- Suppose you are at the Tropic of Cancer, which has a latitude of 23.5 degrees. The altitude of the north celestial pole as seen from your position is...
- 23.5 degrees
- The temperature of the solar photosphere is about
- 5800 K
- How many stars of 7th magnitude in a small cluster would it take if the cluster were to appear as bright as a single 1st magnitude star?
- Which is least important to an astronomer for observing stars:
ability to photograph or measure for long periods of time
ability to aim the telescope in different directions
- magnifying power
- An eclipse of the sun can only occur when the moon is at...
- new moon
- Ten parsecs is the standard distance selected for the astronomical scale of...
- absolute magnitudes
- Suppose that the moon is seen in the sky some evening. The next evening, it will have moved...
- to the east
- How many constellations in the night sky are accepted by the IAU?
- Observation of the shift of a star's spectrum toward the red or the blue (Doppler shift) enables us to determine the star's...
- radial velocity
- The differences observed in stellar spectra are due primarily to differences in...
- The Zeeman effect describes what changes in spectral lines?
- Line splitting due to intense magnetic fields.
- Shepherd moon of Saturn
- Pandora (or Prometheus)
- moons of Mars
- Phobos and Demos
- Largest rocky surface of any known satellite
- Pluto's moon
- Moon of Neptune with a thin atmosphere
- Earth's moon
- the Moon
- Moon of Saturn that resembles the "Death Star"
- Moon of Neptune with a retrograde orbit
- Highest albedo of any solar system object
- First orbited by Borman, Lovell, and Anders in 1968
- the Moon
- Large satellite of Jupiter with possible oceans of water under a layer of ice
- Geologically diverse satellite of Uranus
- Innermost Galilean satellite
- Moon of Saturn with a thick atmosphere
- Galilean satellite with sulphur volcanos
- Suppose you are at the equator which has a latitude of 0 degrees. The altitude of the north celestial pole as seen from your position is...
- 0 degrees
- All stars of spectral type G2 have approximately the same...
- All eclipsing binaries are also
- spectroscopic binaries
- Which kind of star has the greatest average density:
- neutron star
- Which of the following would you NOT expect to find in the spiral arms of a typical galaxy:
O and B stars
- Globular clusters
- Which is NOT a possible final stage of stellar evolution:
T Tauri stage
- T Tauri stage
- Which type of galaxy has a stellar disk, but has little dust or gas?
- What two observations of an object allow for a determination of the Milky Way's mass?
- an object's velocity and distance from the galactic center
- What characteristic is the same for all stars in a star cluster?
- A good way to determine the distance of a DISTANT star cluster is to...
- compare its H-R diagram with a standard H-R diagram
- Which of these features is NOT characteristic of nuclear fusion:
plentiful energy source
four hydrogen atoms produce one helium atom (net result)
neutrons and positrons are produced
high temperature is needed to overcome elecrostatic
- very large, radioactive nuclei are produced as waste products
- Which is NOT a characteristic of a red giant:
nearly depleted hydrogen fuel in the core
contracted stellar core
iron being formed into heavier elements
cool stellar exterior
expansion of the outer layers of the stellar atmosphere
- iron being formed into heavier elements
- How many stars of 11th magnitude in a small cluster would it take for the cluster to appear as bright as a single 6th magnitude star?
- The Crab nebula is material blown off a _____, which was observed by the Chinese in 1054 AD. At its center we now observe a _____
- supernova; pulsar
- The constellations which are visible in the early evening gradually change throughout one year due to the...
- revolution of the Earth about the Sun
- On September 21, the right ascension of the Sun is about...
- 12 hours
- The Ptolemaic system accounts for retrograde motion by...
- having the planets travel on epicycles
- The ancients thought that rest was the natural state for a material body. Newton's ____ law states that uniform linear motion is just as natural as rest.
- Galileo discovered all of the following except:
the phases of Venus
stars too fain for the naked eye to see
the planet Uranus
the four largest satellites of Jupiter
- the planet Uranus
- If a telescope with an objective lens of three-fot focal lenth is used with an eyepiece of 1/4 inch focal length, the resulting magnification will be...
- The law of universal gravitation was developed by...
- The gravitational attraction between two bodies depends on the distance, r, between them. The attraction varies with the distance as...
- Blue light is of _____ than red light.
- higher frequency and shorter wavelength
- Boston is 90 degrees east of Hawaii. If it is noon in Hawaii, in Boston it would be about...
- Polaris, the North Star, does not appear to move in the sky because...
- it lies approximately over the northern axis of the Earth
- Which type of radiation has the least energetic photons:
- radio waves
- In an object is moving toward you, what effect do you observe in the spectrum of that object?
- it appears blue-shifted
- For what is an interferometer used?
- To improve the angular resolution of radio telescopes
- What do all kinds of electromagnetic energy have in common?
- all have the same speed in a vacuum
- Which of these is the greatest distance:
one billion miles
distance from Earth to the Sun
distance to the planet Pluto
- one parsec
- Beyond 100 parsecs, the distances determined by the method of trigonometric parallaxes become very unreliable because...
- the parallax angles become too small to measure accurately
- How do the escape velocities of the jovian planets compare to those of the terrestrial planets?
- the jovian planets have much higher escape velocities
- What do we learn from the Doppler shift which we observe in the spectrum of a star?
- the star's radial velocity
- Would the moon be a good place to do astronomy?
- Yes; no atmosphere
- How many stars of the sixth magnitude would equal the brightness of a star of the first magnitude?
- Why does a star of type G5 have many absorption lines in its spectrum due to metallic elements such as iron, silicon, titanium, etc., which a star of type B5 shows very few lines of such elements?
- the B star is very hot and nearly all of its metallic atoms are ionized, which makes them incapable of absorbing photons having visible wavelengths
- A star with a complete spectral type of B2V would be referred to as which:
lower main sequence
upper main sequence
- upper main sequence
- What would Jupiter have needed to become a star?
- More mass
- The kind of star which shows strong evidence of molecules in its spectrum would be considered...
- very cool
- When the moon is at third quarter, what time will it rise?
- The minor planets (asteroids) in general follow orbits that lie between the orbits of...
- Mars and Jupiter
- The most recent data from distant supernovae indicates that:
- the expansion of the universe is speeding up
- The Sun rotates once in approximately...
- one month
- a given meteor shower, like the Leonids...
- is visible on approximately the same date each year
- In general, the tail of a comet streams away from the comet in a direction...
- away from the Sun
- The so-called "cosmological principle" is simply the idea that the basic large-scale features of the universe...
- are the same regardless of location
- All of the following may be used to estimate the solar surface temperature except:
the Stefan-Boltzman law
- Kepler's laws
- Which o the following spectral types is hottest:
- Sunspots are associated with distortions in the Sun's...
- magnetic field
- One wavelength that may provide contact with extraterrestrial civilizations is found at...
- 21 cm
- Which are NOT intrinsic variable stars:
- eclipsing variables
- Suppose that in the spectrum of a star the spectral lines are observed to be alternately single and then double in a periodic fashion. The star is probably...
- a spectroscopic binary
- Of the many complex molecules found in interstellar space, most are BASED on which element?
- The "helium flash" occurs at what stage in stellar evolution?
- low mass stars as they become red giants
- The absolute magnitude of the Sun is about...
- The type of intrinsic variable stars usually knows as _______ stars have periods from several hours to about a day. They are often found in globular clusters, and for that reason they are sometimes referred to as cluster variables.
- RR Lyrae
- Cepheid variable stars are useful as distance indicators because they show a definite, simple correlation between the period of light variation and their...
- average absolute magnitude
- The observed slowing of a clock in the vicinity of a black hole is a prediction of...
- general relativity
- Globular clusters form...
- a halo concentric with the center of our galaxy
- The Pleiades cluster of stars is an excellent example of a...
- galactic/open cluster
- The time required for a photon to travel across our galaxy is about ______ years.
- A star that is responsible for causing a nebula to fluoresce (i.e. emit an emission spectrum) is mostly likely a star of type...
- O or B
- How is a technologically advanced civilization characterized in the Drake equation?
- A civilization that can communicate over interstellar distances
- Which of the following is NOT found in the galaxy's spiral arms:
young star clusters
O and B stars
- globular clusters
- A galaxy is at a distance of one billion light years. We see the galaxy...
- the way it was one billion years ago
- The nucleus of our galaxy is located in the direction of the constellation...
- Quasars have their distances measured by what technique?
- Hubble Law
- Pair production can occur if...
- The energy of two photons is greater than the combined mass-energy of a particle-anti-particle pair
- Arcturus is in the constellation...
- The Zodiac is...
- The constellations through which the Sun appears to travel in one year
- The Great Square is in the constellation...
- Declination is measured north and south of the celestial equator in units of...
- the declination of the north celestial pole is...
- 90 degrees
- What was Copernicus' major contribution to astronomy?
- claimed Earth is not the center of the universe
- Two forms of electromagnetic radiation that penetrate the Earth's atmosphere are:
x-rays and visible light
gamma rays and radio waves
ultraviolet and infrared
visible light and radio waves
gamma rays and x-rays
- visible light and radio waves
- Pleiades is in the constellation...
- What is the primary advantage of the Hubble telescope over ground-based telescopes?
- it's above the atmosphere
- primary purpose of a telescope is...
- to collect a large amount of light and bring it to a focus
- The series of lines in the spectrum of hydrogen known as the Balmer series are seen in the visible portion of the spectrum and are characterized by electron transitions up from or down to the level n =
- Capella is in the constellation...
- Antares is in the constellation...
- If you view a hot spectrum through a cloud of gas, what sort of spectrum are you likely to see?
- absorption spectrum
- What problem are adaptive optics used to correct?
- effects of atmospheric turbulence
- what is a problem inherent to all radio telescopes?
- poor angular resolution
- The amount of light reflected by an object is its...
- Which planets are the Jovian planets?
- Jupiter, Saturn, Uranus, Neptune
- Density =
- do the terrestrial or jovian planets have higher densities?
- terrestrial planets
- What is the primary ingredient in Earth's atmosphere?
- The average rate of erosion on the Moon is far less than on Earth because...
- The Moon lacks an atmosphere and free water
- The splitting of spectral lines around sunspots is caused by...
- the Zeeman effect
- Ishtar Terra on Venus is a...
- continental-sized plateau
- A nearby star has a parallax of .2 arcseconds. What is its distance?
- 5 parsecs
- The HR diagram plots...
- luminosity vs. temperature
- Which range of electromagnetic radiation is useful for observing new-born protostars within their gas and dust nebulae?
- A typical solar type star spends most of its life...
- as a main sequence star
- What characteristic of a star cluster is used to determine its age?
- main sequence turn-off
- How far is the nearest star beyond the Sun?
- between 1 and 2 pc away
- What is not the same for each star in a cluster:
distance from earth
relative heavy element abundance
- What is the single most important characteristic in determining the course of a star's evolution?
- A nearby star has a parallax of 0.5 arc seconds. What is its distance?
- 2 pc
- What is the size of a typical white dwarf?
- .01 solar radii
- Which of the following stars has the greatest luminosity:
- F7 Ia
- Interstellar gas is composed mainly of...
- hydrogen and helium
- Some regions of the Milky Way appear dark because...
- Stars in that direction are obscured by interstellar dust
- Which two ingredients are needed to make an emission nebula?
- Hot stars and interstellar gas
- A cloud fragment too small to form a star becomes...
- A brown dwarf
- At what stage of evolution do T Tauri stars occur?
- When a protostar is on the verge of becoming a main sequence star
- What is the last observed stage in the evolution of a low-mass star?
- white dwarf
- What is one of the major differences between Cepheid variables and RR Lyrae variables?
- Cepheids are higher luminosity stars than RR Lyrae variables
- Currently the value of the Hubble constant is thought to be very close to...
- 70 km/s/Mpc
- A one half solar mass protostar is just about to move onto the main sequence. This star will most likely have a main sequence spectral type of...
- Who discovered the first object that eventually became known as a pulsar?
- Jocelyn Bell
- One of the consequences of the collision of two galaxies appears to be...
- a burst of vigorous star birth
- What does the Hubble Law measure?
- The rate of expansion of the universe
- From the Sun, what is the distance to the Galaxy's center?
- 26,000 ly
- What is the classification given to a galaxy with a small nuclear bulge, and loosely wound arms starting from a bar through the nuclear bulge?
- What type of variable star is used to determine the distances to globular clusters?
- RR Lyrae stars
- In the simplified version of Kepler's third law, P^2 = a^3, the units of the orbital period P and the semimajor axis of the ellipse a must be, respectively...
- years and astronomical units
- The vernal equinox is a point on the sky where the ecliptic intersects...
- the celestial equator
- On March 21, the right ascension of the Sun is...
- 0 hours
- Aphrodite Terra and Ishtar Terra are on the planet...
- The system of stellar magnitudes we currently use in astronomy was first used by...
- The vast majority of the first 100 extrasolar planets that have been discovered since 1995 are...
- Jupiter size or larger and orbit close to their parent star
- The resolving power of an individual radio telescope antenna is usually relatively poor because...
- radio wavelengths are relatively large compared to the antenna aperture
- Which are the terrestrial planets?
- Mercury, Venus, Earth, Mars
- A star with a complete spectral type of K5III would be called...
- a giant
- The precession of the Earth completes one cycle in a period of about...
- 26,000 years
- Light travels through space at approximately...
- 186,000 km/sec
- If the moon rises at sunset, its phase is...
- The theories concerning the formation of the solar system indicate that the solar nebula had...
- some initial angular momentum
- What natural barrier tries to prevent two protons from combining?
- electromagnetic repulsion
- Which is not true of the giant planets vs. terrestrial planets? The giant planets:
are more massive
have longer rotation periods
have lower density
are considerably larger in volume
- have longer rotation periods
- The last planet visited by the Voyager 2 spacecraft in August 1989 was...
- The luminosity of a star is determined by its...
- radius and temperature
- The star Tau Ceti has an absolute magnitude of 5.68 and an apparent magnitude of 3.49. The distance to Tau Ceti is...
- less than 10 parsecs
- Which have the most rapid apparent motion in the sky:
- What causes night and day?
- The earth rotates on its axis
- If we were to return tot he Moon and set up a permanent base at the Sea of Tranquility, how many times a year would the Earth rise and set?
- Never; the earth would remain in the same position
- In Provo, I see Polaris at about 40 degrees above the horizon. I go 10 degrees south in latitude. How high above the horizon will Polaris appear at my new location?
- 30 degrees above the horizon
- When light from the concave primary mirror of a telescope is reflected by a small secondary mirror through a hole in the primary to its focus, this is called the...
- Cassegrain focus
- The word "planet" is derived from a Greek word meaning...
- The solar neutrino experiment designed by Raymond Davis has detected a rate of solar neutrinos arriving at the Earth which is...
- about one third of the predicted rate
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