Astronomy Practice Final

1.

1 point

How long does a sunspot cycle last, on average?

between 25 and 35 days

about 11 years

365.25 days

about 7 years

about 76 years

2.

1 point

Electromagnetic radion

has nothing in common with radio waves

is the same as a sound wave

has only the properties of wave

can behave both as a wave and a particle

can only travel in a dense medium

3.

1 point

In general, what can be said about type O and B stars compares to type K and M stars?

They are cooler and older

They are cooler and younger

They are neither hotter not cooler, younger nor older

They are hotter and younger

They are hotter and older

4.

1 point

Planetary orbits

are spaced more closely together as they get further from the sun

are almost circular with low eccentricities

are highly inclined to the ecliptic

have the sun at their exact center

5.

1 point

An iron core cannot support a star because

iron is the heaviest element, and sinks upon differentiation

iron cannot fuse with other nuclei to produce energy

Iron has poor nuclear binding energy

iron supplies too much pressure

iron in the form of a gas, not a solid, in the center of the star

6.

1 point

The temperature of the photosphere is about

11,000 K

3,200 K

5,800 K

Ten Million K

One Million K

7.

1 point

Interstellar gas is composed mainly of

only hydrogen

ammonia, methane, and water vapor

10% of hydrogen, 90% helium by numbers of atoms

some hydrogen but mainly carbon dioxide

90% hydrogen, 9% helium by weight

8.

1 point

The speed of light is 3.00 x 10^8 m/s. If 2.00 kg of mass is converted to energy, how much energy will be produced

9.00 x 10^16 J

6.00 x 10^4 J

1.50 x 10^8 J

6.00 x 10^8 J

1.80 x 10^17 J

9.

1 point

The average density of the Sun is most similar to which object

Mercury

Halley's Comet's nucleus

the Earth

the Moon

Jupiter

10.

1 point

The heaviest nuclei of all are formed

during nova explosions

in the horizontal branch

in the core collapse that sets the stage for Type II supernova

in dense white dwarfs

in the ejection of matter in the planetary nebula

11.

1 point

The outward pressure of hot gas in the Sun

is balanced by the inward gravitational pressure

is increasing the Sun's diameter

is cooling the photopshere

weakens the magnetic field

is responsible for variations in the sunspot cycle

12.

1 point

Two important properties of young neutron stars are

no rotation and no magnetic field

extremely rapid rotation and a weak magnetic field

Extremely slow rotation and a strong magnetic field

extremely rapid rotation and a strong magnetic field

no rotation and a weak magnetic field

13.

1 point

The Schwartzchild radius for a 12 solar mass star is

15 km

3000 km

4 km

36 km

100 km

14.

1 point

Sunspots, are dark splotches on the Sun. Which is true?

they are extremely hot but cooler than the surrounding areas of the sun

they are solid bodies floating on the suns surface

they are extremely cold objects, as cold as Pluto

they are hotter than the surrounding areas of the sun

they are associated with areas of very low magnetic fields

15.

1 point

Binary stars separated enough to resolved in a telescope are called

spectostopic binaries

visual binaries

line of sigh binaries

astrometric binaries

orbital binaries

16.

1 point

The densely packed neutrons of a neutron star cannot balance the inward pull of gravity if the total mass is

Chandrasekhar's limit of 1.4 solar masses

not at least 25 solar masses

between 1.4 and 2.0 solar masses

less than 1.0 solar masses

Greater than the Schwartzchil's limit of 3 solar masses

17.

1 point

As a spaceship nears an event horizon, a clock on the spaceship will be observed

to stop

to run the same as the one on earth

to run slowly

to run faster

to run backwards

18.

1 point

On the H-R diagram, the bright blue stars that dominate the naked-eye sky lie

at the top left

At the lower left

in the middle of the main sequence

at the lower right

at the top right

19.

1 point

The Doppler Shift is used to find

spectostropic binaries

eclipsing binaries

photometric binaries

astometric binaries

visual binaries

20.

1 point

Which is the net result of the proton-proton chain?

4 protons —>1 helium 4 + a positron + a neutrino+ gamma rays

2 protons —>deuterium + a positron + an antineutrino+ X-rays

6 protons —>2 helium 4 + 3 positrons + 3 neutrions + gamma rays

4 protons —>1 Helium 4+ 2 neutrinos + gamma rays

21.

1 point

That Polaris will not always be the pole star is due to

The earth's revolution being slightly less than 365.25 days

precession shifting the celestial pole

the sidereal day being shorter than the solar day

the Solar winds blowing the Earth further from the sun

the Moon following the ecliptic instead of the equator

22.

1 point

Small deviations in a planet's orbital motion

indicate the presence of extensive atmosphere

show we don't fully understand gravitational forces yet

indicate the presence of a powerful magnetic field

imply the presence of a nearby massive body

show the planet's orbit isn't stable

23.

1 point

What is the light-gathering power of an 8 inch telescope compared to a 4 inch telescope

2 times brighter

8 times brighter

32 times brighter

16 times brighter

4 times brighter

24.

1 point

What two things are needed to create an emission nebula

cool stars and interstellar dust

interstellar gas and dust

hydrogen gas and carbon dust

hot stars and interstellar gas, particularly hydrogen

hydrogen fusion and helium ionization

25.

1 point

Black dwarfs are

often made from very low mass protostars that never fuse hydrogen

very common, making up the majority of the dark matter in the universe

rare, for few binary systems are close enough for this merger to happen

rare, for collapsing cores over three solar masses are uncommon

not found yet; the oldest, coldest, white dwarf in the Galaxy has not cooled enough yet

26.

1 point

A star near the lower right of the HR diagram is likely to be

hot, bright, and very large

red, with low luminosity

red, with high luminosity

yellow, with luminosity similar to the Sun

blue, with high luminosity,

27.

1 point

The total energy radiated by a blackbody depends on

the fourth root of its temperature

the fourth power of its temperature

the square of its temperature

the cube of its temperature

the square root of its temperature

28.

1 point

In the Kelvin scale, absolute zero lies at

-373 degrees C

zero K

273 degrees C

29.

1 point

Due to absorption of shorter wavelengths by interstellar dust clouds, distant stars appear

larger

to have a higher radial velocity

bluer

redder

brighter

30.

1 point

The two forms of electromagnetic radiation that experience the least atmospheric opacity are

ultraviolet and infrared waves

visible light and infrared waves

visible light and radio waves

X and gamma radiation

microwaves and gamma waves

31.

1 point

Compared to a type A0 star, a type A9 star is

bluer

more luminous

more massive

cooler

hotter

32.

1 point

How much brighter will a 4th magnitude star appear than a 6th magnitude star

16 times

6.25 times

2.0 times

8 times

2.5 times

33.

1 point

Rigel has an apparent magnitude of +0.18 and Betelegeuse an apparent magnitude of +0.45. What can you conclude from this?

Rigel is brighter than betelguese

Betelgeuse is brighter than Rigel

Betelgeuse must be closer to Earth

Rigel must be closer to earth

Both stars are brighter than the full moon

34.

1 point

In the Lighthouse Model

the period of pulsation slows down due to the drag of the remnant on its field

the star literally turns on and off like a lighthouse beacon

all pulsars must have their poles pointed directly toward us

if the beam sweeps across us, we will detect a pulse of radiation

The period of pulsation must speed up as the neutron star continues collapsing

35.

1 point

A very elongated (egg-shaped) orbit would have an eccentricity of

0

infinity

between 0 and 0.5

.25

1

36.

1 point

For a white dwarf to explode entirely as a Type I supernova its mass must be

3 solar masses, the Schwartzchild limit

at least 0.08 solar masses

1.4 solar masses, the Chandraeskhar limit

100 solar masses, the most massive known stars

20 solar masses, the hubble limit

37.

1 point

Inside the Roche Limit

there is a gap in a planet's magnetic field

hydrogen can only exist in its liquid metallic form

ring systems cannot exist

is where large moons form

large moons are torn apart

38.

1 point

The Primary source of the Sun's Energy is

dark energy

the strong force fusing hydrogen into helium

oxidation of carbon in the core

the weak force creating energy from uranium decay

gravitational collapse of the helium toward the core

39.

1 point

A solar eclipse can only happen during a

full moon

solstice

first quarter moon

new moon

perihelion passage of the sun

40.

1 point

Some regions along the plane of the Milky Way appear dark because

there are no stars in these areas

stars in that region are hidden by interstellar gas

many brown dwarfs in those areas absorb

stars in that region are hidden by dark dust particles

many black holes absorb all light

41.

1 point

The density of interstellar dust is very low, yet it still blocks starlight because

it is so cold it absorbs higher energy protons

The dust particles are about the same size as the light waves they absorb

there is 100 times more opaque gas than dust present in the interstellar medium

the dust particles are irregular in shape

ice particles reflect all light back toward their stars, not toward us