Ast 111 Test 1

Front 1

Radio waves are:

Back 1

a form of light

Front 2

Which person is weightless?

Back 2

A child in the air as she plays on a trampoline.

Front 3

How many arcseconds are in one degree?

Back 3

3,600

Front 4

One star is emitting primarily visible light and another star is emitting primarily infrared light. Which star is hotter?

Back 4

the star emitting visible light

Front 5

What is the purpose of interferometry?

Back 5

It allows two or more small telescopes to achieve the angular resolution of a much larger telescope.

Front 6

Which of the following is smallest?

Back 6

1 light-second

size of a typical planet

1 AU

size of a typical star

Front 7

A solar eclipse occurs only when the Moon is new.

Back 7

true

Front 8

Suppose that a lone asteroid happens to be passing Jupiter on an unbound orbit (well above Jupiter's atmosphere and far from all of Jupiter's moons.) Which of the following statements would be true?

Back 8

The asteroid's orbit around Jupiter would not change, and it would go out on the same unbound orbit that it came in on

Front 9

hich of the following statements does not use the term light-year in an appropriate way?

Back 9

It will take me light-years to complete this homework assignment.

Front 10

Which of the following statements about the celestial sphere is not true?

Back 10

The "celestial sphere" is another name for our universe.

Front 11

Suppose you use the Southern Cross to determine that the south celestial pole appears 40 degrees above your horizon. Then you must be located at ________.

Back 11

latitude 40 degrees south

Front 12

As an interstellar cloud of hydrogen gas shrinks in size, its rate of rotation

Back 12

increases, because its angular momentum is conserved.

Front 13

What do astronomers mean by the Big Bang?

Back 13

the event that marked the beginning of the expansion of the universe

Front 14

if a gas cloud shrinks, it

Back 14

shrinks faster

Front 15

In which of the following cases would you feel weightless?

Back 15

while falling from a roof

Front 16

The ultimate source of energy that powers the Sun is

Back 16

mass energy of hydrogen fusing into helium.

Front 17

One light-hour is the distance light travels in one hour. The speed of light is about 300,000 km/s . How far is 1 light-hour?

Back 17

1.08 billion km (1,080,000,000, or 1.08 ×109 km)

Front 18

X-ray telescope mirrors are very similar to optical telescope mirrors.

Back 18

false

Front 19

Which of the following statements best describes the two principle advantages of telescopes over eyes?

Back 19

Telescopes can collect far more light with far better angular resolution.

Front 20

You are standing on Earth's equator. Which way is Polaris, the North star?

Back 20

on the northern horizon

Front 21

Which of the following observational techniques is most appropriate for measuring Doppler shifts?

Back 21

spectroscopy (taking a spectrum)

Front 22

The difference between speed and velocity is that ________.

Back 22

velocity also includes a direction

Front 23

If your mass is 60 kg on Earth, what would your mass be on the Moon?

Back 23

60 kg

Front 24

Suppose you heat an oven to 400°F and boil a pot of water. Which of the following explains why you would be burned by sticking your hand briefly in the pot but not by sticking your hand briefly in the oven?

Back 24

The water can transfer heat to your arm more quickly than the air.

Front 25

Stars that are visible in the local sky on any clear night of the year, at any time of the night, are called ________.

Back 25

circumpolar

Front 26

Which of the following is not a way light and matter interact?

Back 26

evaporation

Front 27

Which of the following statements is not one of Newton's Laws of Motion?

Back 27

what goes up must come down

Front 28

Which of the following best describes the fundamental difference between two different chemical elements (such as oxygen and carbon)?

Back 28

They have different numbers of protons in their nucleus

Front 29

What conditions are required for a solar eclipse?

Back 29

The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun.

Front 30

Suppose Earth's axis tilt was significantly greater than its current 23.5 degrees, but Earth's rotation period and orbital period were unchanged. Which statement below would not be true?

Back 30

The length of each season (for example, the number of days from the summer solstice to the fall equinox) would be significantly longer than it is now

Front 31

The atomic nuclei of the same element always have the same number of protons.

Back 31

true

Front 32

Which of the following is largest?

Back 32

distance to the nearest star (other than our Sun)

size of Pluto's orbit

1 light-year

size of a typical galaxy

Front 33

Which of the following is a general difference between a planet and a star?

Back 33

Stars glow in infrared and visible light, while planets glow only in the infrared.

Front 34

Which of the following statements about X-rays and radio waves is not true?

Back 34

Neither X-rays nor radio waves can penetrate Earth's atmosphere.

Front 35

Two stars that are in the same constellation:

Back 35

may actually be very far away from each other

Front 36

What is a circumpolar star?

Back 36

a star that always remains above your horizon

Front 37

What do astronomers mean by a constellation?

Back 37

A constellation is a region in the sky as seen from Earth.

Front 38

Thermal radiation is defined as ________.

Back 38

radiation with a spectrum whose shape depends only on the temperature of the emitting object

Front 39

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

Back 39

speed perpendicular to my line of sight

Front 40

The speed of light is about 300,000 km/s (3 × 105 km/s). How far does light travel in 30 seconds?

Back 40

9 million km (9,000,000, or 9 × 106 km)

Front 41

What is nuclear fusion?

Back 41

the process of combining lightweight nuclei to make heavier nuclei

Front 42

Light travels at 300,000 km/sec. About how far does light travel in 10 years?

Back 42

about 10 light-years

Front 43

What is stellar parallax?

Back 43

It is the slight back-and-forth shifting of star positions that occurs as we view the stars from different positions in Earth's orbit of the Sun.

Front 44

Which of the following best describes why we have seasons on Earth?

Back 44

The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year.

Front 45

Which of the following statements about electrons is not true?

Back 45

Electrons orbit the nucleus rather like planets orbiting the Sun.

Front 46

Suppose you kick a soccer ball straight up to a height of 10 meters. Which of the following is true about the gravitational potential energy of the ball during its flight?

Back 46

The ball's gravitational potential energy is greatest at the instant when the ball is at its highest point.

Front 47

Which of the following statements does not use the term angular size or angular distance correctly?

Back 47

The angular distance between those two bright stars in the sky is about 2 meters.

Front 48

Which of the following statements about thermal radiation is always true?

Back 48

A hot object emits more radiation per unit surface area than a cool object.

Front 49

Which of the following is not a general difference between a planet and a star?

Back 49

All planets are made of rock, and all stars are made of gas

Front 50

One light year is about 10 trillion kilometers.

Back 50

true