ASTR FINAL EXAM 2025 COMPLETE QUESTIONBANK WITH NEWEST QUESTIONS & CORRECT DETAILED ANSWER, Exams of Astronomy

Download ASTR FINAL EXAM 2025 COMPLETE QUESTIONBANK WITH NEWEST QUESTIONS & CORRECT DETAILED ANSWER and more Exams Astronomy in PDF only on Docsity!

ASTR FINAL EXAM 2025 COMPLETE

QUESTIONBANK WITH NEWEST

QUESTIONS AND CORRECT DETAILED

ANSWERS (VERIFIED ANSWERS) |

ALREADY GRADED A+

For any object moving uniformly, velocity = distance/time. If so, in the Hubble relationship for the expansion of the universe, V= H 0d, what is the significance of the constant 1 /H 0? Select one: a. It is the inverse of the velocity that the object would have at a standard distance of 10 parsecs. b. It represents the average spacing between objects in the universe at the present time. c. It is merely a constant of proportionality, to allow for the different units of V and d. d. It represents the time since the expansion began, or the age of the universe, assuming the expansion has been uniform. Correct Answer D The cosmic background radiation left over after the Big Bang of the universe and pervading all observable space has an effective blackbody temperature of approximately Select one: a. 273 K.

b. 10 K. c. 3 K. d. 0 K. Correct Answer C The future of the overall universe, in terms of its ultimate evolution and whether it will expand forever or eventually contract again, is determined by which of its parameters? a. the intensity of cosmic microwave background radiation b. the temperature of the gas within it c. the present volume of the universe d. the average density of the matter within it Correct Answer D On the basis of recent results from very bright and very distant type 1a supernovae, what seems to be the situation in our universe regarding the past and present motion of clusters of galaxies. a. We live in a "Flat" universe with an accelerating rate of expansion b we live in a closed universe with a decelerating rate of expansion c. we live in an open universe witha constant rate of expansion given by hubbles law d. we live in a "flat" universe with a deceleraing rate of expansion Correct Answer A You can calculate the mass of a galaxy using a.Stefan-Bozman Law b. Wein's Law c. Hubble Law

d. Kepler's Third Law Correct Answer D Convert 26,000 ly to AU: ______ X 10^9 AU Correct Answer 1. Star S0-2 orbits SGR A at the galactic center with an orbital period of 15.2 years and a semimajor axis of 980 AU. What is the mass of SGR A? a. 980^3/15.2^2 = 4.1 x 10^6 Mgal b. 15.2(980^3) = 11.4 ^9 Mgal c. 15.2^2/980^3 = 4.1 x 10^6 Mgal d. 980^2/15.2^3 = 10^6 Mgal Correct Answer A If a galaxy is receding from earth at 6300 km/second in the Hubble Flow, what is the distance? a. 70 Mpc b. 180 Mpc c. 90Mpc d. 6300 Mpc Correct Answer C A galaxy is found to have a distance of 500 Mpc, according to Hubble Law, what will it's recessional velocity be? _______km/s Correct Answer 35,

From Urbana, a star rises exactly due East. When this star reaches its highest position above the horizon, where will it be? a. Directly overhead b. high in the northern sky c. high in the eastern sky d. high in the western sky e. high in the southern sky Correct Answer E From Urbana at midnight, you see a star between Polaris and the horizon. When will this star set? a. 6 hours later b. 12 hours later c. 24 hours later d. Depends on the time of year because the tilt of the earth shifts the stars by 23.5 degrees e. Never Correct Answer E Mars is moving in retrograde motion. Over the course of several nights, how will Mars appear to move relative to the background stars? a. moves randomly since mars moves differently than the stars b. moves east to west c. moves west to east d. breaks a move e. doesn't move at all, since Mars does not move with the stars Correct Answer B

How long is one day on the moon? (how long does it take for the sun to rise and set on the moon? a. 24 hours b. 12 hours c. 1 month d. 1 year e. 23.5 hours Correct Answer c The phase of the moon tonight is 3rd quarter. What will the phase be in 2 weeks? a. 1st quarter b. waxing crescent c. waning crescent d. waning gibbous e. waxing gibbous Correct Answer A The moon rises a couple of hours before sunrise. What phase is it? a. 1st quarter b. waxing gibbous c. waning gibbous d. waxing crescent e. waning crescent Correct Answer E Spectral lines are of particular importance in astronomy because

a. then planets can be distinguished from stars b. they can be observed through diffraction grating c. each different element has a characteristic line spectrum d. only stars produce bright line spectra e. they are the only light bright enough to be seen at large distances. Correct Answer C The milky way galaxy contains: a. dozens of stars b. hundreds of stars. c. millions of stars. d. several hundred billion stars. Correct Answer D If you follow the arc of the Big Dipper handle to the next bright star in the sky, you will find a. Betelgeuse. b. Spica. c. Polaris. d. Arcturus. Correct Answer D As seen from Earth, the Sun appears to move around the celestial sphere along a circular path called the ecliptic. How long does it take the Sun to take one complete trip around the ecliptic? a. One day b. One lunar month c. One year d. One millennium Correct Answer C The vernal equinox occurs in

Select one: a. March. b. June. c. September. d. December. Correct Answer A In a penumbral lunar eclipse a. all parts of the Moon are partly (not totally) shaded from the Sun. b. no points on the Moon are shaded from the Sun, either totally or partially. c. some points on the Moon are totally shaded from the Sun, while others are only partly shaded. d. all of the Moon is shaded from the Sun. Correct Answer A Which Greek astronomer used observations of the Sun's position at noon on the summer solstice at Alexandria and Syene to determine the circumference of the Earth? a. Aristotle b. Eratothenes c. Aristarchus d. Plato Correct Answer B Which astronomer was able to determine the correct method for determining the relative distances to the Sun and Moon, perhaps as long ago as 280 B.C.? Select one: a. Aristotle

b. Eratothenes c. Aristarchus d. Plato Correct Answer C The planet Venus can never reach which planetary configuration, when viewed from Earth? a. Opposition b. Inferior conjunction c. Superior conjunction d. Greatest western elongation Correct Answer A In positional astronomy, two astronomical objects are said to be in _________ when they are on opposite sides of the celestial sphere, as observed from a given body (usually Earth). Correct Answer Opposition What did Galileo see when he observed Jupiter through his telescope? a. Phases like the Moon's phases b. A set of rings c. Nothing interesting because Jupiter is perpetually cloud- covered d. Four moons orbiting Jupiter Correct Answer D The major contribution of Johannes Kepler to the development of modern astronomy was to Select one: a. develop the first mathematical heliocentric model of the solar system. b. observe the satellites (moons) of Jupiter.

c. use parallax to prove that Earth moves around the Sun. d. prove that planetary orbits are ellipses. Correct Answer D Kepler's first law states that a planet moves around the Sun in Select one: a. an elliptical orbit, with the Sun on the minor axis of the ellipse. b. an elliptical orbit, with the Sun at the center of the ellipse. c. a circle, with the Sun at the center. d. an elliptical orbit, with the Sun at one focus. Correct Answer D To which point in a planetary orbit does the word "aphelion" refer? Select one: a. The precise center of the orbit b. The point farthest from the Sun c. The "other" focus (the one not occupied by the Sun) d. The point closest to the Sun Correct Answer B Suppose that a planet of the same mass as Earth were orbiting the Sun at a distance of 10 AU. The gravitational force on this planet due to the Sun would be Select one:

a. 100 times the gravitational force the Sun exerts on Earth. b. 10 times the gravitational force the Sun exerts on Earth. c. 1/10 of the gravitational force the Sun exerts on Earth. d. 1/100 of the gravitational force the Sun exerts on Earth. Correct Answer D Light travels at the same speed regardless of the medium through which it travels. Select one: a. True b. False Correct Answer B A photon is a positively charged particle in the atomic nucleus. Select one: a. True b. False Correct Answer B The higher an object's temperature, the longer the wavelength at which it emits light most strongly. Select one: a. True b. False Correct Answer B How does the speed of light in glass compare to the speed of light in a vacuum?

Select one: a. The speed of light is the same in both. b. The speed of light in glass is faster. c. Depending on the glass, the speed of light can be faster or slower. d. The speed of light in glass is slower. Correct Answer D The speed of light Select one: a. was first accurately determined by Galileo in an experiment involving lanterns and shutters. b. can be determined by observing the motions of the moons of Jupiter. c. was not determined until the advent of lasers in 1960. d. is too high to measure and consequently is still unknown. Correct Answer B Light of a single wavelength falls on a screen with two narrow, closely spaced slits. On a second screen, a short distance beyond the first, Select one: a. nothing will be seen since light cannot pass through narrow slits. b. two bright lines corresponding to the two slits will be observed. c. a totally random mixture of light and dark will be seen. d. a series of bright lines with dark spaces in between will be seen. Correct Answer D

Choose the correct sequence of electromagnetic radiations, in order of increasing wavelength. Select one: a. Radio, IR, visible, UV b. UV, visible, radio, IR c. UV, visible, IR, radio d. Visible, UV, IR, radio Correct Answer C What is the wavelength of electromagnetic radiation whose frequency is 10 ^6 cycles per second (10 ^6 Hz or 1000 kHz, the frequency of ordinary AM radio)? Select one: a. 3 mm b. 3 cm c. 3 m d. 300 m Correct Answer D The temperature of a normal, healthy, human being (37°C) expressed on the Kelvin (absolute) scale is approximately Select one: a. 137 K. b. 410 K. c. 310 K. d. 236 K. Correct Answer C The average temperature of Mars is lower than that of Earth. If a distant observer measures the infrared radiation from both Mars and Earth, then

Select one: a. the emission from the two planets will peak at the same wavelength, but that from Mars will be less intense than that from Earth. b. the wavelength of peak emission from Earth will be longer than that from Mars. c. the wavelength of peak emission from Mars will be longer than that from Earth. d. it is not possible to predict the behavior of the radiation from the information given. Correct Answer C A piece of iron is heated from 400 to 800 K (127 to 527°C). By what factor will the total energy per second emitted by this iron increase? Select one: a. 2 b. 296. c. 4 d. 16 Correct Answer D The main reason for building large optical telescopes on Earth's surface is Select one: a. to increase national prestige, with no scientific reason. b. to collect more light from faint objects. c. to bring astronomical objects closer for more detailed examination by scientists.

d. to magnify images of objects and produce higher resolution photographs. Correct Answer B Approximately what percentage of the light falling on a typical photographic plate from a telescope is actually used to record an image on this plate? Select one: a. 25% b. 50% c. 98% d. 2% Correct Answer D Energy moves almost as fast as the speed of light from the core of the Sun to the surface. Select one: a. True b. False Correct Answer B The surface temperature of the Sun is approximately 15 million Kelvin. Select one: a. True b. False Correct Answer B What is the Sun's energy source? Select one:

a. Primordial heat left over from the release of gravitational energy when the Sun first formed b. Radioactivity c. Thermonuclear fusion in the core d. Heat released by gravitational contraction Correct Answer C The total time that the Sun will spend converting hydrogen to helium in its core is Select one: a. less than 1 million years. b. at least 200 billion years (2 · 10 11) years. c. about 4.5 million years. d. about 10 billion years (10 10 years). Correct Answer D The Sun has existed for a very long time without change in its size, appearance, or behavior. This means that it must be in hydrostatic equilibrium. Under these conditions, which two parameters must be in exact balance within the Sun? Select one: a. Numbers of hydrogen and helium nuclei b. Hydrogen gas pressure and helium gas pressure c. Inward force of gravity and outward gas pressure d. Magnetic field and force of gravity Correct Answer C The two most important processes by which energy is transported from the core of the Sun to the photosphere are

Select one: a. conduction and convection. b. radiation and convection. c. radiation and conduction. d. radiation and neutrino emission. Correct Answer B The mechanism at work when energy is transmitted by convection is Select one: a. the successive exchange of radiant energy between atoms. b. the passage of radiation through a gas. c. the fusion of hydrogen nuclei into helium nuclei. d. the mass motion of hot gases. Correct Answer D What is the Sun's photosphere? Select one: a. The middle layer of the Sun's atmosphere b. The lowest layer of the Sun's atmosphere c. The envelope of convective mass motion in the outer interior of the Sun d. The upper layer of the Sun's atmosphere Correct Answer B The photosphere is the level of the Sun from which most of the visible radiation we see originates. The temperature of the base of the Sun's photosphere is roughly

Select one: a. 600 K. b. 6000 K. c. 60,000 K. d. one million K. Correct Answer B The granulation pattern seen on the surface of the Sun results from Select one: a. heating of the photosphere by solar flares. b. the differential rotation of the Sun. c. strong magnetic fields cooling the gas in certain regions. d. convection of gas in the region under the photosphere. Correct Answer D The corona of the Sun has a temperature Select one: a. of about 10 K, because it merges with cold interstellar space. b. about the same as the photosphere—about 6000 K. c. noticeably less than the photosphere—about 1000 to 2000 K. d. of 1 to 2 million K. Correct Answer D A star's color depends on its surface temperature. Select one: a. True b. False Correct Answer B

Binary stars are two stars that lie along nearly the same line of sight but are actually at very different distances from us. Select one: a. True b. False Correct Answer B Stellar parallax is the Select one: a. elliptical motion of a star in a binary system, as the two stars orbit around each other. b. difference between the apparent magnitude and the absolute magnitude of a star. c. assumed change in the distance to a star when it dims, as it passes through an interstellar cloud. d. apparent shift in the position of a nearby star because of Earth's motion. Correct Answer D If a nearby star shows a parallax of 0.5 arcseconds when Earth moves through 1 AU, at what distance is it from Earth in light-years? Select one: a. 2 parsecs b. 5 parsecs c. 20 parsecs d. 50 parsecs Correct Answer A

Suppose that, at night, the brightness of a light bulb is measured from a certain distance and then the light bulb is moved to a distance twice as far away. How bright will the light appear compared to the earlier measurement? Select one: a. 1/16 as bright b. 1/2 as bright c. 1/8 as bright d. 1/4 as bright Correct Answer D The spectrum of an ordinary main sequence star is a Select one: a. continuum of colors crossed by dark absorption lines, caused by absorption of cooler atoms and molecules at the surface. b. smooth continuum of color, peaking at a specific wavelength whose position is dependent on the surface temperature. c. series of emission lines, mostly from hydrogen, the major constituent of stellar surfaces, that occasionally overlap to produce sections of continuous color. d. continuum of colors crossed by brighter lines caused by emission of hot atoms and molecules on the surface. Correct Answer A Which of the following spectral classifications of stars is in correct order of increasing temperature? Select one:

a. ABFGKMO b. KMGFABO c. MKGFABO d. OBAFGKM Correct Answer C The star Spica is classified as B1 V, which means that it is a Select one: a. cool main sequence star. b. cool giant. c. hot supergiant. d. hot main sequence star. Correct Answer D What proportion of visible stars in the night sky are multiple-star systems? Select one: a. About 25% b. Less than 1% c. Nearly 100% d. About 50% Correct Answer D The blue color of a reflection nebula is produced by Select one: a. light emitted by the gas cloud that is Doppler-shifted as the cloud moves rapidly toward us. b. the continuum emission of very hot gas and dust. c. emission from specific transitions in hydrogen gas.

d. selective scattering from very small dust grains. Correct Answer D Where are protostars most likely to form? Select one: a. Emission nebulae b. Reflection nebulae c. Dark nebulae d. Planetary nebulae Correct Answer C Which are the two most abundant elements in the universe? Select one: a. Hydrogen and helium b. Nitrogen and oxygen c. Hydrogen and oxygen d. Hydrogen and carbon Correct Answer A Protostars are stars Select one: a. that are slowly contracting and cooling. b. whose surfaces are slowly expanding while their cores are contracting. c. that are slowly contracting and heating up. d. that are slowly heating up and expanding. Correct Answer C

The major source of energy in the premain-sequence life of the Sun was Select one: a. gravitational. b. nuclear fusion. c. chemical burning of carbon atoms. d. nuclear fission. Correct Answer A What is the lowest mass that an object can have and still be a star? Select one: a. 0.08 solar masses b. 0.02 solar masses c. 0.002 solar masses (twice Jupiter's mass) d. 0.80 solar masses Correct Answer A A planetary nebula is Select one: a. the nebula caused by the supernova explosion of a massive star. b. a cloud of gas and dust surrounding newly formed planets from which their moons will eventually form. c. the atmosphere of a red giant star slowly expanding away from the star's core to form a shell of gas. d. a disk-shaped nebula of dust and gas rotating around a relatively young star, within which planets will eventually form. Correct Answer C

Stars that have ejected a planetary nebula go on to become Select one: a. red giants. b. white dwarfs. c. protostars. d. supernovae Correct Answer B A Type la supernova is the Select one: a. explosion of a massive star that has lost its hydrogen- rich outer layers through a stellar wind or mass transfer in a binary star system. b. explosion of a white dwarf in a binary star system after mass has been transferred onto it from its companion. c. collapse of a blue supergiant star to form a black hole. d. explosion of a massive star after silicon burning has produced a core of iron nuclei. Correct Answer B At first it was thought that nothing could ever escape from a black hole, yet astronomers are now locating black hole candidates by the X-rays they emit. Do they really see X- rays coming from a black hole? Select one: a. The X-rays come from highly compressed matter in the accretion disk outside the event horizon of the black hole.

b. The black hole modifies spacetime around it so much that particles and X-rays are created in the vacuum itself, just outside the event horizon. c. The X-rays are produced by vibrations of the black hole itself, and therefore they come from the event horizon, and not from inside the black hole. d. X-rays are not light or matter, therefore they can escape from inside the black hole. Correct Answer A Black holes are so named because Select one: a. they emit a perfect blackbody spectrum. b. no light or any other electromagnetic radiation can escape from inside them. c. all their electromagnetic radiation is gravitationally redshifted to the infrared, leaving no light in the optical region. d. they emit no visible light, their only spectral lines being in the radio and infrared. Correct Answer B The formation of an iron core is an important stage in the development of a supernova because Select one: a. iron nuclei cannot participate in nuclear reactions. b. when iron nuclei undergo nuclear reactions, they always absorb energy. c. when iron nuclei undergo nuclear reactions, they always give out energy. d. iron nuclei make the core magnetic. Correct Answer A

Dark matter is probably mostly made from dark nebulae. Select one: a. True b. False Correct Answer B Globular clusters are Select one: a. a class of clusters of stars that are associated with a galaxy, but lie outside the plane. b. a class of groups of large spiral galaxies. c. globules of gas surrounding a planetary nebula. d. groups of stars that are in the spiral arms in the plane of the galaxy. Correct Answer A Variable stars, such as Cepheid variables and RR Lyrae stars, are used in what important measurement in astronomy? Select one: a. Rotation speeds of galaxies b. Surface temperature measurement c. Distance measurement d. The keeping of accurate time Correct Answer C Harlow Shapley first located the center of our galaxy in 1917 by Select one: