Astronomy Practice Exam 3

question

Which of the following parts of the Sun is the hottest one?
answer

Core
question

The Sun’s core is generating energy in the form of?
answer

Gamma rays
question

Which part of the Sun is covered with granules and supergranules?
answer

Photosphere
question

The solar wind is created in the Sun’s?
answer

Corona
question

What is the name of a sudden, highly energetic, eruptive explosion on the surface of the Sun?
answer

Flare
question

The surface temperature of the Sun can be measured using____.
answer

Wien’s law
question

The temperature at the Sun’s core is about _____.
answer

15,000,000 K
question

The Sun’s composition by the % of mass is 71%____, 27%____ and 2%_____.
answer

Hydrogen; helium; other elements
question

The energy in the Sun’s core is produced by _____.
answer

Fusion of hydrogen to helium
question

Light travels for about ____ to reach the Sun’s surface from the Sun’s core, and about _____ to reach the Earth from the Sun’s surface.
answer

16 million years; 8 minutes
question

Astronomers believe that ___ and ___ are manifestations of the Sun’s ____.
answer

Flares; prominences; magnetic field
question

_____ provides a way to measure the speed of seismic waves in the Sun.
answer

The Doppler effect
question

The Sun’s ___ is about ___ at the equator and ____ at the poles.
answer

Rotation period; 25 days; 35 days
question

A solar prominence is essentially?
answer

a plasma confined to a magnetic tube sticking out of the surface of the Sun
question

One way to probe the rate of nuclear reactions in the center of the Sun is by studying the ___ produced because _____.
answer

Neutrinos, they pass out of the Sun without undergoing a random walk
question

Since nuclear fusion in the Sun creates energy from matter, why does it not violate the law of conservation of energy?
answer

Matter and energy are equivalent, as expressed by Einstein’s equation E=mc
question

From the center out, the correct order of the parts of the Sun is___.
answer

Core, radiative zone, convection zone, photosphere, chromosphere, corona
question

The Zeeman effect, in which energy levels of electrons are shifted and produce a corresponding split in spectral lines observed, is used to measure _____ at the Sun’s surface.
answer

Magnetic field strength
question

The solar cycle is a result of the ____.
answer

Differential rotation of the Sun
question

What is parallax?
answer

The apparent shift in position of an object caused by a change in the observer’s position.
question

Star A and Star B have same temperatures, but Star A is more luminous than Star B. Based on this information, which of the following must be the case?
answer

Star A is larger than Star B
question

The relative brightness of the stars as we see them in our sky is represented by their ____.
answer

Apparent magnitude
question

Luminosity (absolute brightness) of a star depends on its _____ and _____.
answer

Temperature and Radius
question

Which of the following star has the hottest stellar surface temperature?
answer

B2
question

Which of the following stars is reddish in color?
answer

K9
question

A star has a parallax angle of 0.25 arcseconds. It is therefore at a distance of?
answer

4 parsecs
question

The H-R diagram is a diagram plotting the stars according to their_____.
answer

Luminosity and temperature
question

The star Aldebaran is a red giant, and is much more luminous than the Sun. What conclusions can be drawn from this fact
answer

Aldebaran is cooler than the Sun, but has larger diameter than the Sun
question

Which of the following is a main sequence star hotter than the sun? (Note: the Sun is a G2V star)
answer

G1V star
question

Which of the following statements would explain the fact that larger molecules, such as amino acids, do not produce spectral lines in the OBAFGKM classification?
answer

Larger molecules break apart at the high temperatures of stellar atmospheres
question

Binary star systems are very important because they allow ____.
answer

Measurements of star masses
question

What is difference between spectroscopic and visual binaries?
answer

In a visual binary we can see two distinct stars; in spectroscopic binaries, the images of the two stars cannot be resolved
question

The study of eclipsing binary stars is very important because it allows astronomers to determine ____.
answer

The diameters of Stars
question

Stars on the main sequence have different luminosities because _____.
answer

They have different masses
question

What can we conclude about a star because its luminosity varies in an irregular pattern?
answer

The star is very young or the star is very old
question

The parallax method for determining distances is ____ that uses the ___ as the baseline.
answer

A triangulation; astronomical unit
question

The amount of energy emitted by as star each second is the ___ and is measured in ___
answer

Luminosity; Watts
question

Analysis of stellar spectra shows that most stars consist of 71% _____, 27% ____ and a 2% mix of the other elements.
answer

Hydrogen; Helium
question

An M type star is 1000 times more luminous than the sun will be located near the ___ part of the H-R diagram.
answer

Top right
question

The hydrogen absorption lines are the strongest in ____ type stars.
answer

A
question

Lines from molecules are strongest in the cool ___ type stars.
answer

M
question

_____ binary stars are important they allow astronomers to determine the mass and the ____ of the stars in the system
answer

Eclipsing; Temprature
question

A main sequence star has 2 times the mass of the Sun. Using ____ we find that the star is ____ times more luminous than the Sun.
answer

The mass-luminosity relation; 8
question

The space between the stars is known to contain _____.
answer

Both gas (atomic or molecular) and dust
question

When do we say that a star is born?
answer

When fusion of hydrogen atoms into helium atoms start
question

What stars form the slowest?
answer

K and M
question

The period-luminosity law of pulsating variable stars indicates that?
answer

The more slowly a star pulsates, the more luminous it is
question

Which of the following elements in your body is formed in stars?
answer

Carbon, Oxygen, Calcium, Iron
question

The Sun will leave the main sequence in about ____ years from now.
answer

5 billion
question

Of all the stages below describing the evolution of a star, which stage does the star spends the longest time ____.
answer

The main sequence
question

When the outer envelope of a red giant is ejected, the remaining core of a low mass star is called a _____.
answer

White dwarf
question

What makes variable stars useful in determining star distances?
answer

Their luminosity can be determined from their pulsation period
question

Which of the following statements about planetary nebulas is correct?
answer

They are shells of glowing gas and dust ejected by dying Sun-like stars; They contain flakes of carbon and silicon material; They expand at a typical rate of 20 kilometers per second; Their shape can be very irregular
question

Which of the following statements about the evolution of high-mass stars is not correct?
answer

High-mass stars have an intense helium flash
question

How do most of the heavier elements up to iron form in the Universe?
answer

By nucleosynthesis in the cores of massive stars
question

How do astronomers test models of stellar evolution?
answer

By comparing the paths in the H-R diagram predicted by models with H-R diagrams of star clusters
question

For a star like the sun, the gravitational collapse of the interstellar cloud lasted for about ____ and stopped with the ignition of the fusion reaction.
answer

1-10 million years
question

A protostar becomes a main-sequence star when it ____.
answer

Starts fusing hydrogen to helium
question

The typical temperature of an interstellar cloud that could collapse to a protostar is about ____.
answer

10 K
question

A _____ is a region where jets of gas from young stars impact and heat the gas surrounding the young star.
answer

Bipolar outflow
question

A protostar is not ____.
answer

In hydrostatic equilibrium
question

The triple alphas process produces energy by fusing ___ into ____.
answer

Helium; Carbon
question

High-mass stars become ____ variables when they cross the instability strip, while low-mass stars become ____ variables.
answer

Cepheid; RR Lyrae
question

The light curve of a large Cepheid variable would typically show pulsations in luminosity _______.
answer

Every 60 days
question

The last fusion product possible in stars is ____ because ___.
answer

Iron, fusing iron nuclei absorbs energy, it does not liberate it.
question

supernova remnants _______, _______, _______.
answer

Initially expand at thousands of km/s; May contain up to 10 solar masses of material ejected from the star; Are important for mixing material into the interstellar medium
question

What factor determines the kind of life a star is going to lead?
answer

Mass of star
question

In the above HR diagram sketch, which star is a white dwarf ?
answer

E
question

In the above diagram HR diagram sketch, which star is a red giant?
answer

D
question

In the above HR diagram, which main sequence star us biggest in size?
answer

A

Get instant access to
all materials

Become a Member