astronomy test #!

A star that is 50 pc away will show a parallax of _____. 0.02 arcseconds 0.02 arcminutes 50 arcseconds 50 arcminutes

0.02 arcseconds

What is our Cosmic Address? In other words, rank the following from nearest to most distant. local group, lanieaka, solar system, interstellar universe, infinite universe (multiverse), observable universe, earth

1. Earth Solar System Interstellar Neighborhood Milky Way Local Group Lanieakea Observable Universe Infinite Universe (Multiverse?)

You take a spectra of a star and notice it has strong absorption lines that indicate the molecule titanium oxide. What is its spectral type? O A G M

M

Put the spectral types in order of increasing temperature (coolest to hottest). G O M A

MGAO

The energy required to transition a photon from n=3.7 to n=5 in a hydrogen atom is _____ the energy required to transition from n=5 to n=2 less than greater than equal to None of the above.

None of the above.

The energy difference between the n=1 and n=3 levels of the hydrogen atom corresponds to a wavelength of 102.5 nm. If a hydrogen atom with its electron in the n=1 level encounters a photon with a wavelength of 102 nm, which of the following happens? the atom does not absorb the photon and it passes by without interaction. The atom absorbs the photon but the electron only moves to the n=2 level. The atom absorbs the photon but the electron only remains in the n=3 level for a very short time before falling back to the n=1 level. The atom absorbs the photon, but nothing happens to the electron.

The atom absorbs the photon but the electron only moves to the n=2 level.

What is an Astronomical Unit (AU)? The average distance between the Sun and Earth. The diameter of Earth's orbit. The average distance between the Sun and the edge of the Solar System. The average distance between Earth and the Moon.

The average distance between the Sun and Earth.

When light from a hot, dense object is passed through a prism or diffraction grating, a _______________ spectrum is produced. continuous absorption emission ionization

continuous

You take the spectra of a star, and notice its Hα line is doppler shifted from its rest wavelength of 656 nm to 655 nm. What can you conclude about this star? It is approaching us at -457,317 m/s. It is moving away from us at +457,317 m/s. It is approaching us at +457,317 m/s. It is approaching us at -457,317 m/s.

It is approaching us at -457,317 m/s.

Assume Earth were moved to a distance from the Sun twice that of what it is now. How would that change the gravitational force it would experience from the Sun? It would be half as strong. It would be one-fourth as strong. It would be twice as strong. It would be four times as strong.

It would be one-fourth as strong.

Two stars are of equal luminosity. Star A is 3 times as far from you as star B. Star A appears ______ star B. 9 times brighter than 3 times brighter than the same brightness as 1/3 as bright as 1/9 as bright as

1/9 as bright as

Two stars are the same luminosity but lie at different distances, for one d=2 pc and the the other, d=8 pc. According to the inverse square law, the more distant one will be fainter by a factor of _____. 2 4 8 16

16

How many stars are there in our galaxy? Selected Answer: 4 × 10^5 4 × 1011 10^17 10^21

4 × 10^11

According to Wien's law, a star like the Sun, with T=5800 K, will have a peak wavelength of ____ nm which is in the ____ part of the electromagnetic spectrum. 500; ultraviolet 500; visible 1.7 x 1010; visible 1.7 x 1010; radio

500; visible

If an electromagnetic wave's frequency is increased, then its energy is increased. its wavelength is decreased. its color is changed from "redder" to "bluer" All of the above are the result of an increase in frequency.

All of the above are the result of an increase in frequency.

A hydrogen atom that has been photoionized is _____. an ion a proton positively charged All of the above.

All of the above.

If the Sun instantaneously stopped giving off light, what would happen on Earth? Earth would get dark 1 hour later. Earth would immediately get dark. Earth would get dark 27 minutes later. Earth would get dark 8 minutes later.

Earth would get dark 8 minutes later.

You examine the spectra of two stars, A & B, and determine that they are the same spectral type. Their spectra appear to have equally strong absorption lines of hydrogen and helium, but Star A has a very strong line for oxygen at 630.2 nm. You examine Star B's spectra but find an oxygen line also present at 630.2, but is much weaker. What can you conclude about these two stars? Star A and B are the same spectral type, but Star A has more oxygen in its atmosphere than Star B. Star A and B are the same spectral type, but Star A is approaching us faster than Star B. Star A and B different spectral types. Star A and B are the same spectral type, but Star B is rotating much slower than Star A.

Star A and B are the same spectral type, but Star A has more oxygen in its atmosphere than Star B.

Star A has an apparent magnitude m = 0 and Star B has an apparent magnitude of m = +5. How do these stars' brightness compare? Star A appears 5 times fainter than Star B. Star A appears 100 times fainter than Star B. Star A appears 100 times brighter than Star B. Star A appears 5 times fainter than Star B.

Star A appears 100 times brighter than Star B.

Star A and star B appear equally bright in the sky. Star A is twice as far away from Earth as star B. How do the luminosities of stars A and B compare? Star A is 4 times as luminous as star B. Star B is 4 times as luminous as star A. Star A is 2 times as luminous as star B. Star B is 2 times as luminous as star A.

Star A is 4 times as luminous as star B.

You take the spectra of two stars, A and B. Star A's spectral lines have a positive doppler shift and Star B's lines have a negative doppler shift. What can you conclude about these two stars? Star A is moving away from us and Star B is moving toward us. Star A is moving toward us and Star B is moving away from us. We cannot tell until we know the exact values of their doppler shift.

Star A is moving away from us and Star B is moving toward us.

You take the spectra of two stars, A and B. Star A's spectral lines have a positive doppler shift and Star B's lines have a negative doppler shift. What can you conclude about these two stars? Star A is moving away from us and Star B is moving toward us. Star A is moving toward us and Star B is moving away from us. We cannot tell until we know the exact values of their doppler shift.

Star A is moving away from us and Star B is moving toward us.

What is the main reason why different stars have different spectra? Different stars are located in different regions of the Milky Way galaxy. Stars have different temperatures. Different stars are made of significantly different elements. Some stars have atmospheres while others do not.

Stars have different temperatures.

All stars rotate, but some rotate more rapidly than others. How can we determine a star's rotation rate? Take multiple pictures of the star to make a movie of it rotating. Faster-rotating stars exhibit a strong blueshift. Rotating stars are much less luminous than stationary stars of the same spectral type. Stars that rotate have much wider lines in their spectra than stars that do not.

Stars that rotate have much wider lines in their spectra than stars that do not.

When an electron moves from a higher energy level in an atom to a lower energy level, a photon is absorbed. a photon is emitted. a continuous spectrum is emitted. a redshifted spectrum is emitted.

a photon is emitted.

In order for an electron in a hydrogen atom to increase its energy level from n=2 to n=3, it must emit a photon with a wavelength of 6560 Å. absorb a photon with a wavelength of 6560 Å. emit a photon with a wavelength between 4100 Å and 6560 Å. absorb a photon with a wavelength between 4100 Å and 6560 Å.

absorb a photon with a wavelength of 6560 Å.

An atom is ionized when it _______ a photon of very _____ wavelength, causing the electron to leave the atom entirely.

absorbs; short absorbs; long emits; short emits; long

When light from a hot, dense object passes through a cloud of cool gas before it is passed through a prism or diffraction grating, a _______________ spectrum is produced. continuous absorption emission ionization

absorption

The spectrum of the Sun is ____ because it is a ______. continuous; hot 5800 K dense blackbody emission; hot 5800K gas absorption; hot dense interior surrounded by a cooler 5800 K layer

absorption; hot dense interior surrounded by a cooler 5800 K layer

Kepler's second law states or implies that while traveling in their orbits, the plane sweep out equal areas in equal times. move fastest when they are the closest to the Sun. move slowest when they are the farthest from the Sun. Correct all of these answers are correct

all of these answers are correct

Recombination is the process by which ____. wo atoms bond in a molecule nuclei fuse together to form new elements the energy of a photon removes an electron from an atom an electron joins with a positively charged ion

an electron joins with a positively charged ion

The temperature of an object has a very specific meaning as it relates to the object's atoms. A high temperature means that the atoms are moving very fast. are all moving together. have a lot of energy. are very large.

are moving very fast.

The "square" in the inverse square law for intensity of light means that at three times the distance, the intensity is 1/3 as great. at three times the distance, the intensity is 1/9 as great. at three times the distance, the intensity is three times greater. at three times the distance, the intensity is nine times greater.

at three times the distance, the intensity is 1/9 as great.

The "square" in the inverse square law for intensity of light means that at three times the distance, the intensity is three times greater. at three times the distance, the intensity is nine times greater. at three times the distance, the intensity is 1/9 as great. at three times the distance, the intensity is 1/3 as great.

at three times the distance, the intensity is 1/9 as great.

Suppose the mass of the Moon were to double. The gravitational force between the Earth and Moon will remain the same. be twice as strong on the Earth but the same on the Moon. be twice as strong on the Moon but the same on the Earth. be twice as strong between the Earth and Moon.

be twice as strong between the Earth and Moon.

Consider two stars of the same size. One has a surface temperature of T=3,000 K and other with T=6,000 K. The two stars will differ in the sense that the hotter star will be ____ because according to Wien's law, its peak wavelength will be a factor of ______ than that of the cooler star. bluer; 2 shorter (half as long) bluer; 2 longer (twice as long) redder; 2 shorter (half as long) redder; 2 longer (twice as long)

bluer; 2 shorter (half as long)

Kepler's first law states that the orbits of the planets are ellipses with the Sun in the center. ellipses with Earth at one of the foci. ellipses with the Sun at one of the foci. always perfectly circular with the Sun in the center.

ellipses with the Sun at one of the foci.

Two stars have the same apparent brightness but parallax measurements show that star A lies at 5 pc while star B is 10 pc away. We can apply the inverse square law to conclude that star A is ____ than star B. four times less luminous two times more luminous four times more luminous two times less luminous

four times less luminous

Studies of the spectra of stars have revealed that the element that makes up the majority of the stars (75% by mass) is stellarium. hydrogen. helium. carbon.

hydrogen

A main sequence O star will have a ___ temperature, a ____ radius, a ____ luminosity and a ____ absolute magnitude than a main sequence G star like the Sun. larger, larger, larger, smaller larger, larger, larger, larger larger, smaller, larger, smaller smaller, smaller, smaller, larger

larger, larger, larger, smaller

The energy required to transition a photon from n=3 to n=5 in a hydrogen atom is _____ the energy required to transition from n=5 to n=2 less than greater than equal to None of the above.

less than

Which the following forms of electromagnetic radiation is listed from longest to shortest wavelength gamma, microwave, ultraviolet, blue long radio, infrared, yellow, ultraviolet x-ray, ultraviolet, infrared, radio infrared, green, microwave, far ultraviolet

long radio, infrared, yellow, ultraviolet

As a blackbody becomes hotter, it also becomes __________ and __________. less luminous; bluer more luminous; redder more luminous; bluer less luminous; redder

more luminous; bluer

As a blackbody becomes hotter, it also becomes __________ and __________. more luminous; bluer less luminous; bluer less luminous; redder more luminous; redder

more luminous; bluer

A star with T=10,000 K (spectral type A) shows strong absorption lines from _______. the molecule titanium oxide, TiO. neutral hydrogen (H I) ionized helium (He II) neutral iron (Fe I)

neutral hydrogen (H I)

A star with T=10,000 K (spectral type A) shows strong absorption lines from _______. the molecule titanium oxide, TiO. Correct neutral hydrogen (H I) ionized helium (He II) neutral iron (Fe I)

neutral hydrogen (H I)

A star with T=10,000 K (spectral type A) shows strong absorption lines from _______. the molecule titanium oxide, TiO. neutral hydrogen (H I) ionized helium (He II) neutral iron (Fe I)

neutral hydrogen (H I)

Two stars are the same size. One with T=3,000 and the other with T=6,000. They will differ in the sense that the hotter star will have a luminosity that is ______ that of the cooler star, according to the Stefan-Boltzmann law. 2 times lower 2 times higher four times higher sixteen times higher

sixteen times higher

The B-V color index of an O star will be ____ the B-V index of a G star like the Sun. smaller than greater than the same as cannot determine, as it depends on distance

smaller than

Compared to your mass on Earth, on the Moon your mass would be lower because the Moon is smaller than Earth. the same, mass doesn't change. higher because of the combination of the Moon's mass and size. lower because the Moon has less mass than Earth.

the same, mass doesn't change.

Which the following forms of electromagnetic radiation is listed from highest to lowest energy levels? gamma, microwave, ultraviolet, blue long radio, infrared, yellow, ultraviolet x-ray, ultraviolet, infrared, radio infrared, green, microwave, far ultraviolet

x-ray, ultraviolet, infrared, radio