quiz 2

Question 1

According to the universal law of gravitation, the force due to gravity is

inversely proportional to the square of the distance between objects.

not dependent on the distance between objects.

directly proportional to the square of the distance between objects.

directly proportional to the distance between objects.

Answer 1

inversely proportional to the square of the distance between objects.

Question 2

At which lunar phase(s) are tides least pronounced (e.g., the lowest high tides)?

both first and third quarters
both new and full moons
new moon
first quarter

Answer 2

both first and third quarters

Question 3

According to the universal law of gravitation, if you double the masses of both attracting objects, then the gravitational force between them will

increase by a factor of 4.
decrease by a factor of 2.
decrease by a factor of 4.
not change at all.

Answer 3

increase by a factor of 4.

Question 4

The tides on Earth are an example of

the universal law of gravitation.
Newton’s third law of motion.
Newton’s first law of motion.
Newton’s second law of motion.

Answer 4

the universal law of gravitation.

Question 5

What is the acceleration of gravity at the surface of Earth?

9. 8 m/s^2 downward
10. 8 m/s downward
11. 8 km/s^2 downward
12. 8 m^2/s downward

Answer 5

9.8 m/s^2 downward

Question 6

The force of gravity is an inverse square law. This means that, if you double the distance between two large masses, the gravitational force between them

weakens by a factor of 4.
also doubles.
strengthens by a factor of 4.
weakens by a factor of 2.

Answer 6

weakens by a factor of 4.

Question 7

The planets never travel in a straight line as they orbit the Sun. According to Newton’s second law of motion, this must mean that ________.

a force is acting on the planets
the planets have angular momentum
) the planets will eventually fall into the Sun
No answer text provided.

Answer 7

a force is acting on the planets

Question 8

How does a rocket launch upwards? Choose the statement that best describes why a rocket goes up.

By expelling gas downwards, the rocket is propelled upwards.
By expelling gas downwards, which pushes against the ground, the rocket is propelled upwards.
By expelling gas, the rocket loses mass; because it is lighter, it rises up.

Answer 8

By expelling gas downwards, the rocket is propelled upwards.

Question 9

A net force acting on an object will always cause a change in the object’s ________.

momentum
speed
mass

Answer 9

momentum

Question 10

Newton’s Second Law of Motion tells us that the net force applied to an object equals its ________.

mass times acceleration
mass times energy
momentum times velocity
mass times velocity

Answer 10

mass times acceleration

Question 11

Suppose you are in an elevator that is traveling upward at constant speed. How does your weight compare to your normal weight on the ground?

It is the same.
It is greater.
It is less.
You are weightless.

Answer 11

It is the same.

Question 12

Suppose you lived on the Moon. Which of the following would be true?

Your weight would be less than your weight on Earth, but your mass would be the same as it is on Earth.
Your mass would be less than your mass on Earth, but your weight would be the same as it is on Earth.
Both your weight and your mass would be less than they are on Earth.
Both your weight and your mass would be the same as they are on Earth.

Answer 12

Your weight would be less than your weight on Earth, but your mass would be the same as it is on Earth.

Question 13

Suppose the Sun were suddenly to shrink in size but that its mass remained the same. According to the law of conservation of angular momentum, what would happen?

The Sun would rotate faster than it does now.
The Sun’s rate of rotation would slow.
The Sun’s angular size in our sky would stay the same.
This could never happen, because it is impossible for an object to shrink in size without an outside torque.

Answer 13

The Sun would rotate faster than it does now.

Question 14

Which of the following represents a case in which you are not accelerating?

driving in a straight line at 60 miles per hour
going from 0 to 60 miles per hour in 10 seconds
slamming on the brakes to come to a stop at a stop sign
driving 60 miles per hour around a curve

Answer 14

driving in a straight line at 60 miles per hour

Question 15

When a spinning ice skater pulls in his arms, he spins faster because ________
his angular momentum must be conserved, so reducing his radius must increase his speed of rotation
there is less friction with the air
there is less friction with the ice
there exists an unbalanced reaction force

Answer 15

his angular momentum must be conserved, so reducing his radius must increase his speed of rotation

Question 16

If a gas cloud shrinks, it

spins faster.
spins at the same rate as it did before it shrank.
spins slower.

Answer 16

spins faster.

Question 17

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

increases, because its angular momentum is conserved.
decreases, because its angular momentum is conserved.
increases, because its total energy is conserved.
increases, because the force of gravity strengthens as the cloud shrinks.

Answer 17

increases, because its angular momentum is conserved.

Question 18

The energy attributed to an object by virtue of its motion is known as ________.

kinetic energy
potential energy
radiative energy
mass-energy

Answer 18

kinetic energy

Question 19

The amount of gravitational potential energy released as an object falls depends on

the distance it falls.
its speed at the time it begins falling.
the distance it falls and its speed at the time it begins falling.
neither the distance it falls nor its speed at the time it begins falling.

Answer 19

the distance it falls.

Question 20

Which of the following statements correctly describes the law of conservation of energy?

The total quantity of energy in the universe never changes.
An object always has the same amount of energy.
Energy can change between many different forms, such as potential, kinetic, and thermal, but it is ultimately destroyed.
The fact that you can fuse hydrogen into helium to produce energy means that helium can be turned into hydrogen to produce energy.
It is not really possible for an object to gain or lose potential energy because energy cannot be destroyed.

Answer 20

The total quantity of energy in the universe never changes.

Question 21

Gasoline is useful in cars because it has

  chemical potential energy. 
  gravitational potential energy. 
  kinetic energy. 
  radiative energy. 
  electrical potential energy.

Answer 21

chemical potential energy.

Question 22

If I drop a golf ball and a bowling ball simultaneously from same height above the ground, what will happen? Neglect the effects of wind or air resistance.

The golf ball and the bowling ball will hit the ground at the same time.
The bowling ball will hit the ground before the golf ball.
The golf ball will hit the ground before the bowling ball.
No answer text provided.

Answer 22

The golf ball and the bowling ball will hit the ground at the same time.

Question 23

If a gas cloud shrinks, its gravitational potential energy is converted into

thermal energy and radiative energy.
kinetic energy and sound waves.
only radiative energy.
chemical energy.

Answer 23

thermal energy and radiative energy

Question 24

What does temperature measure?
the average kinetic energy of particles in a substance
the average mass of particles in a substance
the total potential energy of particles in a substance
the total amount of heat in a substance

Answer 24

the average kinetic energy of particles in a substance

Question 25

The ultimate source of energy that powers the Sun is mass energy of hydrogen fusing into helium. gravitational potential energy of the contraction of the gas cloud that formed the Sun. chemical potential energy of hydrogen burning into helium. thermal energy of the hydrogen atoms in the Sun.

Answer 25

mass energy of hydrogen fusing into helium.

Question 26

From shortest to longest wavelength, which of the following correctly orders the different categories of electromagnetic radiation? radio, infrared, visible light, ultraviolet, X-rays, gamma rays gamma rays, X-rays, visible light, ultraviolet, infrared, radio gamma rays, X-rays, ultraviolet, visible light, infrared, radio infrared, visible light, ultraviolet, X-rays, gamma rays, radio

Answer 26

gamma rays, X-rays, ultraviolet, visible light, infrared, radio

Question 27

The stars in our sky twinkle in brightness and color because of ________. turbulence in the Earth's atmosphere the bubbling and boiling of gases on the surfaces of stars light pollution rapid changes in the brightnesses and colors of stars caused by changes in their spectra

Answer 27

turbulence in the Earth's atmosphere

Question 28

Which of the following statements about X-rays and radio waves is not true? X-rays have higher frequency than radio waves. X-rays have shorter wavelengths than radio waves. X-rays travel through space faster than radio waves. X-rays and radio waves are both forms of light, or electromagnetic radiation.

Answer 28

X-rays travel through space faster than radio waves.

Question 29

Which of the following statements is true of green grass? It absorbs red light and reflects green light. It transmits all colors of light except green. No answer text provided. It absorbs red light and emits green light.

Answer 29

It absorbs red light and reflects green light.

Question 30

Suppose you know the frequency of a photon and the speed of light. What else can you determine about the photon? No answer text provided. the chemical composition of the object that emitted it its temperature its wavelength and energy

Answer 30

its wavelength and energy

Question 31

From laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 121.6 nanometers (nm). The spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 121.8 nm. What can we conclude? The "star" actually is a planet. The star is moving away from us. The star is getting colder. The star is moving toward us.

Answer 31

The star is moving away from us.

Question 32

Consider an atom of carbon in which the nucleus contains 6 protons and 7 neutrons. What is its atomic number and atomic mass number? atomic number = 6; atomic mass number = 13 atomic number = 13; atomic mass number = 6 atomic number = 7; atomic mass number = 13 atomic number = 6; atomic mass number = 7

Answer 32

atomic number = 6; atomic mass number = 13

Question 33

Which of the following best describes the fundamental difference between two different chemical elements (such as oxygen and carbon)? They have different numbers of protons in their nucleus. They have different numbers of electrons. They have different names. They have different atomic mass numbers.

Answer 33

They have different numbers of protons in their nucleus.

Question 34

The diagram represents energy levels in a hydrogen atom. The labeled transitions (A through E) represent an electron moving between energy levels. Which labeled transition represents an electron that absorbs a photon with 10.2 eV of energy? D A C B

Answer 34

B

Question 35

The energies of two photons you might detect emitted by hydrogen atoms are 10.2 and 2.1 eV. Which photon has the longest wavelength? No answer text provided. the 10 eV photon the 2.1 eV photon They both have the same wavelength

Answer 35

the 2.1 eV photon

Question 36

``` The most common isotope of gold has atomic number 79 and atomic mass number 197. How many protons and neutrons does the gold nucleus contain? 79 protons and 197 neutrons 118 protons and 79 neutrons No answer text provided. 79 protons and 118 neutrons ```

Answer 36

79 protons and 118 neutrons

Question 37

``` The most common isotope of oxygen has atomic number 8 and atomic mass number 16. Another isotope has two extra neutrons. What are the atomic number and atomic mass number of this isotope? 6 and 16 8 and 16 8 and 14 8 and 18 ```

Answer 37

8 and 14

Question 38

Compare the energy and speed of infrared and visible light. Which of the following statements is true? Visible light has higher energy, but the same speed. Infrared light has higher energy, and moves faster. Infrared light has higher energy, but the same speed. Visible light has higher energy, and moves faster.

Answer 38

Visible light has higher energy, but the same speed.

Question 39

The most common isotope of gold has atomic number 79 and atomic mass number 197. Assuming the gold is electrically neutral, how many electrons does it have? 197 118 No answer text provided. 79

Answer 39

79

Question 40

When considering light as made up of individual "pieces," each characterized by a particular amount of energy, the pieces are called ________. frequencies photons gamma rays wavicles

Answer 40

photons

Question 41

The frequency of a wave is equal to the speed of the wave divided by the wavelength of the wave. measured in cycles per second. all of the above measured in hertz (Hz).

Answer 41

all of the above

Question 42

Which of the following is not a way light and matter interact? absorption evaporation emission transmission

Answer 42

evaporation

Question 43

How are wavelength, frequency, and energy related for photons of light? Longer wavelength means lower frequency and lower energy. Longer wavelength means higher frequency and higher energy. There is no simple relationship because different photons travel at different speeds. Longer wavelength means higher frequency and lower energy.

Answer 43

Longer wavelength means lower frequency and lower energy.

Question 44

Which of the following statements about X-rays and radio waves is not true? X-rays have higher energy than radio waves. X-rays and radio waves are both forms of light, or electromagnetic radiation. X-rays have higher frequency than radio waves. Neither X-rays nor radio waves can penetrate Earth's atmosphere.

Answer 44

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

Question 45

An atom of the element iron has an atomic number of 26 and an atomic mass number of 56. If it is neutral, how many protons, neutrons, and electrons does it have? 26 protons, 30 neutrons, 26 electrons 13 protons, 43 neutrons, 13 electrons 26 protons, 30 neutrons, 30 electrons 26 protons, 56 neutrons, 26 electrons

Answer 45

26 protons, 30 neutrons, 26 electrons

Question 46

Which of the following describes the light that can be detected from a person? The person emits a few narrow wavelengths of visible light according to their composition. The person reflects many wavelengths of visible light and emits a continuum of wavelengths of infrared light. The person absorbs a few narrow wavelengths of visible light according to their composition. The person emits many wavelengths of visible light and reflects a continuum of wavelengths of infrared light.

Answer 46

The person reflects many wavelengths of visible light and emits a continuum of wavelengths of infrared light.

Question 47

When an electron drops to a lower energy level in an atom, the electron becomes more massive. the atom moves more slowly. light at a wavelength specific to the change in energy levels is emitted. the extra energy disappears.

Answer 47

light at a wavelength specific to the change in energy levels is emitted.

Question 48

Which of the following properties cannot be determined from a spectrum of a star? chemical composition speed perpendicular to my line of sight speed towards me or away from me surface temperature

Answer 48

speed perpendicular to my line of sight

Question 49

Suppose that Star X and Star Y both have redshifts, but Star X has a larger redshift than Star Y. What can you conclude? Star X is moving away from us faster than Star Y. Star Y is moving away from us faster than Star X. Star X is hotter than Star Y. Star X is moving away from us and Star Y is moving toward us.

Answer 49

Star X is moving away from us faster than Star Y.

Question 50

The spectra of most galaxies show redshifts. This means that their spectral lines ________. have wavelengths that are shorter than normal have a higher intensity in the red part of the spectrum always are in the red part of the visible spectrum have wavelengths that are longer than normal

Answer 50

have wavelengths that are longer than normal

Question 51

How does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope? Hint: light collecting are is equal to \pi.\left(\frac{D}{2}\right)^2 π . ( D 2 ) 2 where D is the diameter of the light collecting area. The 8-meter telescope has 4 times the light-collecting area of the 2-meter telescope. The answer cannot be determined from the information given in the question. The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope. The 8-meter telescope has 8 times the light-collecting area of the 2-meter telescope.

Answer 51

The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope.

Question 52

What is the purpose of adaptive optics? It allows several small telescopes to work together like a single larger telescope. It is a special technology that allows the Hubble Space Telescope to adapt to study many different types of astronomical objects. It reduces blurring caused by atmospheric turbulence for telescopes on the ground. It allows ground-based telescopes to observe ultraviolet light that normally does not penetrate the atmosphere.

Answer 52

It reduces blurring caused by atmospheric turbulence for telescopes on the ground.

Question 53

The Chandra X-ray Observatory must operate in space because_____________. It was built by NASA. X-rays do not penetrate Earth's atmosphere. X-ray telescopes require the use of grazing incidence mirrors. X-rays are too dangerous to be allowed on the ground.

Answer 53

X-rays do not penetrate Earth's atmosphere.

Question 54

Which of the following observational techniques is most appropriate for measuring Doppler shifts? spectroscopy (taking a spectrum) No answer text provided. imaging (taking a picture) timing (measuring how the amount of light changes with time)

Answer 54

spectroscopy (taking a spectrum)

Question 55

Why is the Earth's daytime sky blue? Molecules absorb more red light than blue light. Molecules scatter blue light more than red light. Air molecules are blue in color. The sky reflects the blue of the oceans and lakes.

Answer 55

Molecules scatter blue light more than red light.

Question 56

Which of the following statements about thermal radiation is always true? A hot object produces more total infrared emission than a cooler object. A cold object produces more total infrared and radio emission per unit surface area than a hot object. All the light emitted by hot object has higher energy than the light emitted by a cooler object. A hot object emits more radiation per unit surface area than a cool object.

Answer 56

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

Question 57

Doppler shifted hydrogen absorption lines are seen in the spectrum of a star. The hydrogen line at 656.28 nm is seen to be shifted to 656.08 nm. How large is the fractional shift in wavelength? Hint: fractional shift in wavelength = Δ λ / λ . Here, Δ λ is the small change or shift in wavelength and λ is the normal wavelength when the source is not moving. about 0.0003 ( or 3 E-4) about 0.03 (3 E-2) about 0.000003 (or 3E-6) about 0.2

Answer 57

about 0.0003 ( or 3 E-4)

Question 58

What is the purpose of interferometry? It allows two or more small telescopes to achieve the angular resolution of a much larger telescope. It reduces the twinkling of stars caused by atmospheric turbulence. It allows two or more small telescopes to achieve a larger light-collecting area than they would have independently. It is designed to prevent light pollution from interfering with astronomical observations.

Answer 58

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

Question 59

The spectra of most galaxies show redshifts. This means that their spectral lines ________. have wavelengths that are shorter than normal always are in the red part of the visible spectrum have a higher intensity in the red part of the spectrum have wavelengths that are longer than normal

Answer 59

have wavelengths that are longer than normal

Question 60

Which of the following objects would be most likely to produce an emission-line spectrum? a star like our Sun the Earth a neon light a light bulb

Answer 60

a neon light

Question 61

According to the laws of thermal radiation, hotter objects emit photons with ________. a lower average energy a higher average speed a lower average frequency a shorter average wavelength

Answer 61

a shorter average wavelength

Question 62

Betelgeuse is the bright red star representing the left shoulder of the constellation Orion. All the following statements about Betelgeuse are true. Which one can you infer from its red color? It is much brighter than the Sun. It is much more massive than the Sun. It is moving away from us. Its surface is cooler than the surface of the Sun.

Answer 62

Its surface is cooler than the surface of the Sun.

Question 63

Doppler shifted hydrogen absorption lines are seen in the spectrum of a star. The hydrogen line at 656.28 nm is seen to be shifted to 656.08 nm. How large is the shift in wavelength? No answer text provided. 0.02 nm 0.2 nm 2 nm

Answer 63

0.2 nm

Question 64

The stars in our sky twinkle in brightness and color because of ________. light pollution rapid changes in the brightnesses and colors of stars caused by changes in their spectra the bubbling and boiling of gases on the surfaces of stars turbulence in the Earth's atmosphere

Answer 64

turbulence in the Earth's atmosphere

Question 65

Studying a spectrum from a star can tell us a lot. All of the following statements are true except one. Which statement is not true? The total amount of light in the spectrum tells us the star's radius. We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals. Shifts in the wavelengths of spectral lines compared to the wavelengths of those same lines measured in a laboratory on Earth can tell us the star's speed toward or away from us. The peak of the star's thermal emission tells us its temperature: hotter stars peak at shorter (bluer) wavelengths.

Answer 65

The total amount of light in the spectrum tells us the star's radius.

Question 66

Suppose you want to know the chemical composition of a distant star. Which piece of information is most useful to you? the peak energy of the star's thermal radiation whether the star's spectrum has more emission lines or more absorption lines the wavelengths of spectral lines in the star's spectrum the Doppler shift of the star's spectrum

Answer 66

the wavelengths of spectral lines in the star's spectrum

Question 67

Doppler shifted hydrogen absorption lines are seen in the spectrum of a star. The hydrogen line at 656.28 nm is seen to be shifted to 656.08 nm. Is the star moving towards or away from us, or can we not tell? No answer text provided. There is not enough information to determine the answer. moving towards us moving away from us

Answer 67

moving towards us

Question 68

Thermal radiation is defined as ________. radiation that is felt as heat radiation in the form of emission lines from an object radiation with a spectrum whose shape depends only on the temperature of the emitting object No answer text provided. radiation produced by an extremely hot object

Answer 68

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

Question 69

What do astronomers mean by light pollution? Light pollution is light from human sources that makes it difficult to see the stars at night. Light pollution is a type of air pollution created by lightweight gases such as hydrogen and helium. Light pollution means contamination of light caused by chemicals in the Earth's atmosphere. Light pollution is a term used to describe the appearance of the sky in regions that are crowded with stars.

Answer 69

Light pollution is light from human sources that makes it difficult to see the stars at night.