Astronomy Midterm

Front 1

The average distance from Earth to the sun

Back 1

1 AU

Front 2

If the distance to the nearest star is 4.2 light-years, then

Back 2

the light we see left the star 4.2 years ago

Front 3

If light takes 8 minutes to travel from the sun to Earth and over 4 hours to travel from the sun to the planet Neptune, what is the distance from the sun to Neptune?

Back 3

30 AU

Front 4

The apparent visual magnitude of a star is 7.3. This tells us that the star is

Back 4

not visible with the unaided eye

Front 5

A totally eclipsed moon glows coppery red because

Back 5

only red light is able to pass completely through Earth's atmosphere and reach the moon

Front 6

If the north celestial pole appears on your horizon, what is your latitude?

Back 6

0º

Front 7

The ______ is 18 years and 11 1/3 days long.

Back 7

saros cycle

Front 8

Northern Hemisphere winters are colder than Northern Hemisphere summers because

Back 8

c and d

Front 9

A waxing crescent moon is visible

Back 9

near the western horizon just after sunset.

Front 10

The diagram below shows three approximate locations of the sun along the western horizon. Which number indicates the location of the sun at sunset on June 21 for an observer at a latitude of 37º N?

Back 10

3

Front 11

Parallax is

Back 11

the apparent motion of an object due to the motion of the observer

Front 12

Newton concluded that a force from the Earth had to act on the moon because

Back 12

a force is needed to accelerate the moon toward Earth away from straight-line motion.

Front 13

Kepler's second law implies that

Back 13

a planet should move at its greatest speed when it is closest to the sun.

Front 14

The purpose of using epicycles to explain the motion of the planets in the night sky was to account for

Back 14

retrograde motion

Front 15

The greatest inaccuracy in Copernicus' model of the solar system was that the planets

Back 15

travel in circular orbits with uniform motion.

Front 16

Ultraviolet radiation from a star

Back 16

will not penetrate Earth's atmosphere and reach the ground.

Front 17

The energy of a photon

Back 17

is inversely proportional to the wavelength of the light.

Front 18

Which of the following types of electromagnetic radiation has the highest frequency

Back 18

gamma-rays

Front 19

The technique of connecting multiple telescopes together to combine the images from each telescope is known as

Back 19

interferometry.

Front 20

Which of the following types of electromagnetic radiation has the smallest frequency?

Back 20

radio

Front 21

Radio telescopes are _____ telescopes.

Back 21

Reflecting

Front 22

Which has the larger light-gathering power?

Back 22

A telescope of 6 cm diameter and focal length of 100 cm.

Front 23

The resolving power of a telescope is ____.

Back 23

a measure of the minimum angular separation that can be seen with the telescope.

Front 24

In the diagram, which of the transitions would absorb a photon with the smallest energy (longest wavelength)?

Back 24

Transition 5

Front 25

The diagram illustrates a light source, a gas cloud, and three different lines of sight. Along which line of sight would an observer see an absorption spectrum?

Back 25

3

Front 26

____ has a negative charge and a mass about 1800 times small than a proton.

Back 26

An electron

Front 27

Which of the following can be determined by using the Doppler Effect?

I. The speed at which a star is moving away from an observer.

II. The traverse velocity of a star.

III. The radical velocity of a star.

IV. The speed at which a car is traveling toward an observer.

Back 27

I, III, & IV

Front 28

Which of the following cannot be determined from the spectrum of a star?

Back 28

Tangential (perpendicular to line of sight) velocity?

Front 29

The sunspot cycle affects ____.

I. the latitude at which most sunspots occur

II. the number of sunspots that are visible.

II. The rotation rate of the sun's equator.

IV. the magnetic polarity of the sunspot pair members in a hemisphere.

Back 29

I, II, & IV [5th one]

Front 30

The sun's magnetic field is evident in the looped shapes of

Back 30

prominences

Front 31

A star's luminosity depends on

Back 31

temperature and diameter

Front 32

Interstellar gas clouds may collapse to from stars if they

Back 32

encounter a shock wave.

Front 33

The lowest mass object that can initiate thermonuclear fusion of hydrogen has a mass of about

Back 33

0.08 solar masses

Front 34

What characteristic of a star primarily its location on the main sequence

Back 34

mass

Front 35

____ is a form electromagnetic radiation produced by rapidly moving spiraling through magnetic fields.

Back 35

Synchroton radiation

Front 36

Stars in a star cluster

Back 36

a and b above. (all have the same age and all have the same chemical composition)

Front 37

After what evolutionary stage does a star become a white dwarf?

Back 37

Giant

Front 38

The _____ of a black hole is the radius from a black hole at which the escape velocity is approximately equal to the speed of light.

Back 38

event horizon

Front 39

A neutron star is expected to spin rapidly because

Back 39

they conserved angular momentum when they collapsed.

Front 40

The absorption lines in the visible portion of the spectrum of a star that are produced by hydrogen are from the

Back 40

Balmer series

Front 41

If you move an electron in an atom from a low energy level to a higher energy level within the atom, we say that the atom is

Back 41

an excited atom.

Front 42

Each element has its own set of characteristic absorption lines because

Back 42

electron energy levels differ for each element

Front 43

Granulation is caused by

Back 43

rising and sink gases below the photosphere.

Front 44

The ___ coincides with the period known as the "little ice age" of Europe and North America. This provides one piece of evidence that suggests a link between solar activity and the amount of solar energy Earth receives.

Back 44

Maunder sunspot minimum.

Front 45

___ is (are) produced by atomic transitions in the presence of a strong field.

Back 45

The Zeeman effect

Front 46

What causes the outward gas pressure that balances the inward pull of gravity in a main sequence star?

Back 46

c and d (the high temperature of the gas & the high density of the gas)

Front 47

In the proton-proton chain

Back 47

energy is produced in the form of gamma rays and the velocity of the created nuclei.

Front 48

Why do higher mass stars live shorter lives on the main sequence than lower mass stars?

Back 48

Higher mass stars burn through than nuclear fuel faster.

Front 49

The Chandrasekhar limit tells us that

Back 49

white dwarfs more massive than 1.4 solar masses are not stable.

Front 50

A type-II supernova

Back 50

c and d (is characterized by a spectrum that shows hydrogen lines & occurs when the iron core of a massive star collapses)