Mid Term-2 ASTR 1303 Fall 2022 bez otvetov case 102323 (FILLED)

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ASTR 1303 Fall 2022 (base) Chapters 17-22 Midterm 2 Page 1 ASTR 1303 Midterm 2 Fall 2022 Chapter 17 SecƟon 17.1 True or False 17.1.1) The nearest naked-eye star to our Sun, Alpha Centauri, is sƟll over a parsec distant. Answer: ____ True SecƟon Ref: 17.1 17.1.2) First magnitude Spica appears 2.5 Ɵmes brighter than second magnitude Polaris. Answer: _____ False SecƟon Ref: 17.2 17.1.3) If a star were moved 10 Ɵmes farther away, its apparent magnitude would drop by five magnitudes. Answer: _____ False SecƟon Ref: 17.2 17.1.4) A type B9 star is hoƩer than a type A0. Answer: _____ Fasle SecƟon Ref: 17.3 17.1.5) Hydrogen lines are weaker in both very hot and very cool stars. Answer: _____ True SecƟon Ref: 17.3 17.1.6) A star of the Sun's diameter, but twice as hot, must be 16X more luminous than the Sun. Answer: _____ False SecƟon Ref: 17.4 17.1.7) The vast majority of stars near us would fall to the boƩom right on the H-R diagram. Answer: _____ False SecƟon Ref: 17.5 17.1.8) The Sun's complete classificaƟon is G2V. Answer: _____ True SecƟon Ref: 17.6 17.1.9) In a spectroscopic binary, the star whose lines shiŌ the most weighs the most. Answer: _____ False SecƟon Ref: 17.7 17.1.10) Eclipsing binaries are the most useful, giving us sizes as well as masses of the pair. Answer: _____ True SecƟon Ref: 17.7 17.1.11) A star of ten solar masses would probably stay stable on the main sequence only about 1/1000th as long as our Sun. Answer: _____ True SecƟon Ref: 17.8 ======================================================== SecƟon 17.2 MulƟple Choice 17.2.1) A nearby star has a parallax of 0.2 arc seconds. What is its distance? A) .1 parsec B) .2 parsec C) .5 parsec D) 5 parsecs E) 50 parsecs Answer: _____ D SecƟon Ref: 17.1
ASTR 1303 Fall 2022 (base) Chapters 17-22 Midterm 2 Page 2 17.2.2) If a star has a parallax of 0.05" ( “ = arcseconds), then its distance in light years (lys) is about: A) 6.4 lys. B) 12.7 lys. C) 20 lys. D) 65 lys. E) 100 lys. Answer: _____ D SecƟon Ref: 17.1 17.2.3) What is the absolute magnitude of our Sun? A) -23.0 B) -4.6 C) -1.4 D) +4.8 E) +9.4 Answer: _____ D SecƟon Ref: 17.2 17.2.4) The absolute magnitude of a star is its brightness as seen from a distance of: A) one million kilometers. B) one astronomical unit. C) one light year. D) ten parsecs. E) 10 light years. Answer: _____D SecƟon Ref: 17.2 17.2.5) What are the two most important intrinsic properƟes used to classify stars? A) mass and age B) luminosity and surface temperature C) distance and luminosity D) distance and surface temperature E) distance and color Answer: ___B__ 17.2.6) What physical property of a star does the spectral type measure? SecƟon Ref: 17.3 A) density B) luminosity C) temperature D) mass E) composiƟon Answer: __C___ 17.2.7) The star's color index is a quick way of determining its: SecƟon Ref: 17.3 A) density. B) luminosity. C) mass. D) temperature. E) composiƟon. Answer: _____ D SecƟon Ref: 17.3 17.2.8) Stars that have masses similar to the Sun's, and sizes similar to the Earth are: A) main sequence stars. B) white dwarfs. C) red giants. D) red dwarfs. E) brown dwarfs. Answer: _____ E SecƟon Ref: 17.4 17.2.9) Compared to the size of the Sun, in what range of sizes (solar radii) are nearly all stars found? A) .5 to 2 B) 0.1 to 1.0 C) 0.5 to 50 D) 1 to 100 E) 0.01 to 100 Answer: _____ A SecƟon Ref: 17.4 17.2.10) On the H-R diagram, the Sun lies: A) at the top leŌ. B) at the boƩom leŌ. C) at the boƩom right. D) about the middle of the main sequence. E) at the top right. Answer: _____ D SecƟon Ref: 17.5
ASTR 1303 Fall 2022 (base) Chapters 17-22 Midterm 2 Page 3 17.2.11) Which of the following is the most common type of star? A) high mass main sequence B) low mass main sequence C) white dwarfs D) red giants E) blue supergiants Answer: _____ B SecƟon Ref: 17.5 17.2.12) How might the most common occurring stars be described, based on our stellar neighborhood? A) white dwarfs B) K giants C) G main sequence D) A main sequence E) M main sequence Answer: _____ E SecƟon Ref: 17.5 17.2.13) Which type of binary can have their sizes measured directly by photometry? A) virtual B) visual C) eclipsing D) spectroscopic E) astrometric Answer: _____ C SecƟon Ref: 17.7 17.2.14) What is the single most important characterisƟc in determining the course of a star's evoluƟon? A) density B) absolute brightness C) distance D) surface temperature E) mass Answer: ___E__ SecƟon Ref: 17.8 Select the leƩer for the appropriate lifeƟmes below: SecƟon Ref: 17.8 A) one million years B) 20 million years C) ) 100 million years D) one billion years E) ten billion years F) ) 100 billion years G) a trillion years 17.2.15) What is the typical main sequence lifeƟme of an M-type star? Answer: __G__ 17.2.16) What is the typical main sequence lifeƟme of a G-type star? Answer: __D___ 17.2.17) What is the typical main sequence lifeƟme of a B-type star? Answer: ___B__ 17.2.18) For a star of 10 solar masses, its main sequence lifeƟme relaƟve to our Sun will be: A) 10x longer. B) about the same. C) one tenth D) 100x less. E) only 1/1000th. Answer: _____ E SecƟon Ref: 17.8
ASTR 1303 Fall 2022 (base) Chapters 17-22 Midterm 2 Page 4 Chapter 18 SecƟon 18.1 True or False 18.1.1) The "Local Bubble" was probably created by a nearby supernova in the distant past. Answer: _____ True SecƟon Ref: Discovery 18-1 18.1.2) The H I regions are mapped by the radiaƟon created when an electron flips its spin. Answer: _____ False SecƟon Ref: 18.4 18.1.3) The 21 cm line of hydrogen is strongly absorbed by interstellar dust. Answer: _____ False SecƟon Ref: 18.4 18.1.4) Dark dust clouds radiate mainly in the radio porƟon of the electromagneƟc spectrum. Answer: _____ False SecƟon Ref: 18.4 18.1.5) Most molecules found in the giant molecular clouds are based on silicon. Answer: _____ False SecƟon Ref: 18.5 ====================================== SecƟon 18.2 MulƟple Choice 18.2.1) Interstellar gas is composed of: A) only hydrogen. B) 90% hydrogen, 9% helium by weight. C) 10% hydrogen, 90% helium by numbers of atoms. D) some hydrogen, but mainly carbon dioxide. E) ammonia, methane, and water vapor. Answer: _____ B SecƟon Ref: 18.1 18.2.2) Due to absorpƟon of shorter wavelengths by interstellar dust clouds, distant stars appear: A) bluer. B) brighter. C) redder. D) larger. E) to have a higher radial velocity. Answer: _____ C SecƟon Ref: 18.1 18.2.3) Emission nebulae like M42 occur only near stars that emit large amounts of: A) visible light. B) microwaves. C) ultraviolet radiaƟon. D) infrared. E) X-rays & gamma rays. Answer: ____C_ SecƟon Ref: 18.2 18.2.4) A large gas cloud in the interstellar medium that contains several type O and B stars would appear to us as: A) a dark nebula. B) an emission nebula. C) bright blue. D) a reflecƟon nebula. E) a dark patch against a bright background. Answer: _____ B SecƟon Ref: 18.2 18.2.5) Which of these is NOT a consequence of dust in the interstellar medium? A) reddening of stars' light that passes through the dust B) blue reflecƟon nebulae around the Pleiades
ASTR 1303 Fall 2022 (base) Chapters 17-22 Midterm 2 Page 5 C) red light from the emission nebulae D) the dark nebulae that block 90% of the Milky Way from us visually E) terrestrial planets like our own Answer: _____ E SecƟon Ref: 18.2 18.2.6) Astronomers use roman numerals to indicate the ionizaƟon state of a gas. Ionized hydrogen is indicated by which of the following symbols? A) H II B) H2 C) H I D) H 1 1 E) H III Answer: _____ A SecƟon Ref: 18.2 18.2.7) Charles Messier mapped the night sky and idenƟfied many objects now known to be emission nebulae in his search for objects that might be confused with: A) comets. B) asteroids. C) galaxies. D) dark nebulae. E) reflecƟon nebulae. Answer: _____ A SecƟon Ref: 18.2 18.2.8) Interstellar absorpƟon lines are narrow primarily because: A) there is very liƩle interstellar maƩer. B) molecules always produce narrow absorpƟon lines. C) most of the maƩer is ionized, and atoms moving fast produce sharp lines. D) the maƩer is at a low temperature, and atoms are almost sƟll. E) All of the above are correct. Answer: _____ D SecƟon Ref: 18. 3 18.2.9) What informaƟon does 21 cm radiaƟon provide about the gas clouds? A) their moƟon B) their distribuƟon C) their density D) their temperature E) all of these Answer: _____ A SecƟon Ref: 18.4 18.2.10) When an electron in H changes its spin from the same to opposite direcƟon as the proton, it: A) emits an X-ray photon. B) absorbs a radio wave photon. C) emits a radio wave photon. D) absorbs a visible light photon. E) neither emits nor absorbs a photon. Answer: _____ C SecƟon Ref: 18.4 18.2.11) The most common molecule in a molecular cloud is: A) methane, CH4. B) molecular hydrogen, H2. C) carbon monoxide, CO. D) water, H2O. E) ammonia, NH3. Answer: _____ B SecƟon Ref: 18.5
ASTR 1303 Fall 2022 (base) Chapters 17-22 Midterm 2 Page 6 18.2.12) Complex molecules in space are found in: A) photospheres of red giant stars. B) dense dust clouds. C) coronas of stars like our Sun. D) scaƩered evenly throughout interstellar space. E) surrounding the more energeƟc young stars. Answer: _____ B SecƟon Ref: 18.5 18.2.13) Which of the following has NOT yet been observed in space? A) formaldehyde B) methyl alcohol C) DNA D) ammonia E) hydrogen cyanide Answer: _____ C SecƟon Ref: 18.5 18.2.14) Unlike atoms, molecules can: A) rotate. B) vibrate. C) spin. D) Both A and B. E) All of the above. Answer: _____ E SecƟon Ref: 18.5 ============================== Chapter 19 SecƟon - No 19.1 True or False SecƟon 19.2 MulƟple Choice QuesƟons 19.2.1) What makes the subject of star formaƟon so difficult and complex? A) It is so slow that no visible proof of it exists. B) Star formaƟon is too expensive to study in detail. C) Stars live too long to be observed from birth to death. D) Clouds, fragments, protostars, stars, and nebulae all interact and influence each other. E) Shock waves disrupt the orderly evoluƟon of stars. Answer: _____ D SecƟon Ref: 19.1 19.2.2) Our Sun, along with most of the stars in our neighborhood, probably formed: A) a few million years ago. B) about 10 million years ago. C) hundreds of millions of years ago. D) billions of years ago. E) at the beginning of the universe. Answer: _____ D SecƟon Ref: 19.1 19.2.3) What is the force that keeps a main sequence star from blowing apart? A) magneƟsm B) gravitaƟon C) strong force D) radiaƟon pressure E) electron degeneraƟon pressure Answer: _____ B SecƟon Ref: 19.1 19.2.4) Which event marks the birth of a star? A) formaƟon of the planetary nebula B) fusion of hydrogen atoms into helium atoms C) interstellar cloud collapse D) formaƟon of a photosphere E) interstellar cloud instability Answer: _____ C SecƟon Ref: 19.2
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