Astronomy Quizzes 3

Front 1

Suppose you drop a 10-pound weight and a 5-pound weight on the Moon, both from the same height at the same time. What will happen?

Back 1

Both will hit the ground at the same time.

Front 2

Newton showed that Kepler's laws are

Back 2

natural consequences of the law of universal gravitation.

Front 3

Suppose the Sun shrunk in size but its mass remained the same. What would happen to the orbit of the Earth?

Back 3

Earth's orbit would be unaffected.

Front 4

An asteroid moving in an elliptical orbit about the Sun will be travelling fastest when it is

Back 4

closest to the Sun.

Front 5

An asteroid orbiting the Sun in a circular orbit with a radius that is twice that of Earth's orbit would have an orbital period of

Back 5

2.8 years
square root of x^3

Front 6

Consider an astronaut in the Space Shuttle as the Space Shuttle orbits Earth. Is there a gravitational force exerted by Earth on the astronaut?

Back 6

Yes

Front 7

What is a CCD?

Back 7

It is an electronic detector that can be used in place of photographic film for recording images.

Front 8

what causes the twinkling of stars?

Back 8

atmospheric turbulence

Front 9

What is the SINGLE most important feature of an astronomical telescope?
Choose one answer.
a. Greater Magnification.
b. Greater Light Gathering Power.
c. Greater Resolving Power.
d. Greater Color Contrasting Power

Back 9

Greater Light Gathering Power

Front 10

The strength of the gravitational force between two masses, M1 and M2, can be written as F = GM1M2/r2. where r is the distance between the two masses. Accordingly, the strength of the gravitational force depends _____ on M1

Back 10

directly

Front 11

The strength of the gravitational force between two masses, M1 and M2, can be written as F = GM1M2/r2. where r is the distance between the two masses. Which of the following changes would most effect the strength of the gravitational force?
Choose one answer.
a. Changing M2 a little while leaving M1 and r unchanged.
b. changing r a little while leaving M1 and M2 unchanged.

Back 11

b. changing r a little while leaving M1 and M2 unchanged.

Front 12

Which of the following best describes why radio telescopes are generally much larger in size than telescopes designed to collect visible light?

Back 12

Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light.

Front 13

Suppose that the angular separation of two stars is 0.1 arcseconds, and you photograph them with a telescope that has an angular resolution of 1 arcsecond. How will the stars appear in the photograph?

Back 13

Since their angular separation is smaller than the telescope's angular resolution, your photograph will seem to show only one star rather than two.

Front 14

Suppose you point your telescope at a distant object. Which of the following is NOT an advantage of taking a photograph of the object through the telescope as compared to just looking at the object through the telescope?
a. By using a long exposure time, the photograph can allow you to see objects that would be too dim to see with your eye.
b. The photograph provides a more reliable record of what is seen through the telescope than can a drawing made by eye.
c. If taken with a camera with a sensitive detector such as a CCD, the photograph can capture a much larger percentage of the incoming photons than can your eye.
d. The photograph will have far better angular resolution than you can see with your eye.

Back 14

The photograph will have far better angular resolution than you can see with your eye.

Front 15

The stars in our sky twinkle in brightness and color because of

Back 15

turbulence in the Earth's atmosphere.

Front 16

The strength of the gravitational force between two masses, M1 and M2, can be written as F = GM1M2/r2. where r is the distance between the two masses. Accordingly, the strength of the gravitational force depends
directly/inversly on distance r.

Back 16

inversely

Front 17

What do we mean by the diffraction limit of a telescope?

Back 17

It is the angular resolution the telescope could achieve if nothing besides the size of its light-collecting area affected the quality of its images.

Front 18

The Chandra X-ray Observatory must operate in space because:

Back 18

X rays do not penetrate Earth's atmosphere.

Front 19

What is the purpose of interferometry?

Back 19

two or more small telescopes to achieve the angular resolution of a MUCH larger telescope

Front 20

Which of the following best describes the principle advantage of CCDs over photographic film?
Choose one answer.
a. CCDs allow long exposures (e.g., minutes or hours) and film does not.
b. CCDs capture a much higher percentage of the incoming photons than film.
c. CCDs can record the colors of astronomical objects accurately while film cannot.
d. CCDs can be attached to modern telescopes more easily than can photographic film.

Back 20

b. CCDs capture a much higher percentage of the incoming photons than film.

Front 21

How does the light-gathering power of an 8-meter telescope compare to that of a 2-meter telescope?

Back 21

The 8-meter telescope has 16 times the light-gathering power of the 2-meter telescope.

Front 22

Which of the following is NOT an advantage of the Hubble Space Telescope over ground-based telescopes?
Choose one answer.
a. It is closer to the stars.
b. It never has to close because of cloudy skies.
c. It can observe infrared and ultraviolet light, as well as visible light.
d. Stars do not twinkle when observed from space.

Back 22

a. It is closer to the stars is not an advantage because it's barely closer at all

Front 23

Suppose you heat up an oven to 400 degrees 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 23

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

Front 24

The star Sirius has a surface temperature about twice that of the Sun (12,000 Kelvin for Sirius versus 6,000 Kelvin for the Sun). Per unit surface area, how much more energy does Sirius radiate than the Sun?

Back 24

16 times as much energy.

Front 25

T/F: X-rays have shorter wavelengths than radio waves.

Back 25

True

Front 26

Absolute zero is

Back 26

0 degrees Kelvin

Front 27

Which of the following scenarios involves energy that we would typically calculate with Einstein's formula E=mc2?

Back 27

When hydrogen is fused into helium, whether in the Sun or a nuclear bomb, some of the mass disappears and becomes energy.

Front 28

In the formula E=mc2, what does E represent?

Back 28

The mass-energy, or potential energy stored in an object's mass.

Front 29

Suppose a light source is emitting red light at a wavelength of 700 nm and another light source is emitting ultraviolet light at a wavelength of 350 nm. Each photon of the ultraviolet light has _______ the energy of each photon of the red light.

Back 29

twice the energy of each photon of the red light.

Front 30

Radiative energy is

Back 30

energy carried by light

Front 31

What does temperature measure?

Back 31

The average kinetic energy of particles in a substance.

Front 32

What is a joule?

Back 32

It is the standard unit of energy used in science.

Front 33

Suppose you have a 100-watt light bulb that you leave turned on for one minute. How much energy does it use?

Back 33

6,000 joules
1 joule per watt per second

Front 34

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 34

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

Front 35

The energy emitted per second by the Sun is greatest at a wavelength of about 500 nm. The energy emitted per second by a star that is three times hotter than the Sun would be greatest at a wavelength of about

Back 35

170 nm (1/3 of 500 nm)

Front 36

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

Back 36

kinetic energy

Front 37

Suppose the Sun was 4 times hotter than it actually is, but staid the same size. How much more energy per second would the Sun emit?

Back 37

256 times more.

Front 38

If star Zeta emits electromagnetic radiation most intensely at a wavelength of 500 nanometers, what is the surface temperature (in Kelvin) of this star?

Back 38

5,800

Front 39

Which of the following best describes why we say that light is an electromagnetic wave?

Back 39

The passage of a light wave can cause electrically charged particles to move up and down.

Front 40

Gamma rays have a very small

Back 40

wavelength.

Front 41

The graph shows the intensity versus wavelength plots for two different stars, A and B. Which star is emits more blue light?

Back 41

Star A

Front 42

The graph shows the intensity versus wavelength plots for two different stars, A and B. Which star emits more red light?

Back 42

Star A

Front 43

The graph shows the intensity versus wavelength plots for two different stars, A and B. Which star appears red?

Back 43

Star B

Front 44

The graph shows the intensity versus wavelength plots for two different stars, A and B. Which star is hotter?

Back 44

Star A

Front 45

T/F: At the equator, over the course of the year, all 88 constellations will at some point be visible in the evening sky.

Back 45

TRUE

Front 46

T/F: At the equator, there are no circumpolar stars in the equatorial sky.

Back 46

TRUE

Front 47

T/F: At the Earth's equator, the north celestial pole is directly on your horizon, due north (with Polaris quite nearby).

Back 47

TRUE

Front 48

T/F: At the equator, the Sun will pass directly overhead around noon each day.

Back 48

FALSE: at the equator the sun will pass directly overhead on the Vernal and Autmnal Equinoxes

Front 49

how far away is the andromeda galaxy?

Back 49

2.5 million light-years

Front 50

how many AU's in a light year?

Back 50

~63,000

Front 51

arrange in order: solar system, local supercluster, local group, galaxy,

Back 51

solar system
galaxy
local group
local supercluster

Front 52

T/F: X-rays have higher frequency than radio waves.

Back 52

TRUE

Front 53

3 objections to heliocentricism?

Back 53

1.Aristotle: Earth is not moving, or things would fall off
2. Aristotle: heavens are perect, so orbits are perfect circles
3. no stellar parallax

Front 54

Ptolemy? (3)

Back 54

1. geocentric
2. small circles on big circles
3. accurate predictions

Front 55

Copernicus? (3)

Back 55

1. heliocentric
2. heavenly bodies move in perfect circles
3. no more accurate than Ptolemy

Front 56

Tycho Brahe?

Back 56

no model
made observations that kepler would use

Front 57

Kepler?

Back 57

1. orbits are not circles, but elipses
2. equl areas in equal times
3. more distant orbits have slower periods

Front 58

Galileo? (5)

Back 58

Galileo? (5)

1. heliocentric
2. earth can move without things falling off because objects remain in motion until a froce stops them
3. heavens are not perfect: sun spots and moon mountains: so orbits don't have to be circles
4. moons orbit jupiter, so not everything orbits earth
5. venus phases only work if it orbits sun

Front 59

emitted power per square meter of surface =

Back 59

sigma * (T ^ 4)

Front 60

wavelength of max intensity =

Back 60

2,900,000 / T

Front 61

telescope light-collecting area =

Back 61

diameter ^ 2

Front 62

orbital period =

Back 62

square root of (a ^ 3)