Question 1 · 
  If light from a hot, dense star passes through a cool cloud of gas (see Figure 4-9, Comins and Kaufmann, Discovering the Universe, 8th ed.),


Answer · · 1. · only specific wavelengths of light will be removed from the spectrum. · · 2. · the atoms of the gas cloud will add energy to the overall spectrum, · enhancing it at specific wavelengths to produce emission lines. · · · 3. · the whole spectrum will be reduced in intensity. · · 4. · the cool gas will not affect the spectrum of the star because cool atoms · cannot absorb light. · 
 1 points   Question 2 · 
  In the revolution that overtook physics around 1900, the assumption that Planck made in order to solve the problem concerning the spectrum of radiation emitted by a hot blackbody was that radiation was 

Answer · · 1. · emitted in small, discrete packets or quanta of energy whose individual · energies were inversely proportional to the wavelength of the light. · · · 2. · made up of small, discrete packets or quanta of energy whose individual · energies were all the same, independent of wavelength. · · · 3. · emitted as continuous waves whose wavelength was inversely · proportional to the temperature of the object. · · · 4. · emitted in small, discrete packets or quanta of energy, each quantum · having an energy directly proportional to the wavelength of the light. · 
 1 points   Question 3 · 
  The element helium was first discovered and identified as a separate element 

Answer · · 1. · inside meteorites that had come from outer space. · · 2. · on the Sun, from the emitted spectrum from its upper atmosphere. · · 3. · in rocks containing radioactively decaying elements such as uranium. · · 4. · in natural gas originating underground, from the spectrum emitted · from a flame of burning natural gas. · 
 1 points   Question 4 · 
  An atom in which one or more electrons has been removed is known as a(n) 

Answer · · 1. · molecule. · · 2. · excited atom. · · 3. · isotope. · · 4. · ion. · 
 1 points   Question 5 · 
  A particular spectrograph, used by an astronomer to disperse light into its colors, contains a piece of glass that has been ruled with thousands of closely spaced, parallel lines. What is the name of this piece of glass? 

Answer · · 1. · CCD array · · 2. · interferometer · · 3. · diffraction grating · · 4. · prism · 
 1 points   Question 6 · 
  To a physicist, a blackbody is defined as an object that 

Answer · · 1. · reflects all radiation that falls on it, never heating up and always appearing black. · · 2. · always emits the same spectrum of light, whatever its temperature. · · 3. · absorbs all radiation that falls on it. · · 4. · always appears to be black, whatever its temperature. · 
 1 points   Question 7 · 
  A piece of iron is heated from 400 K to 800 K (127°C to 527°C). The total energy emitted per second by this iron will increase by a factor of


Answer · · 1. · 296.5. · · 2. · 4. · · 3. · 2. · · 4. · 16. · 
 ...

1. Question 1
· If light from a hot, dense star passes through a cool cloud
of gas (see Figure 4-9, Comins and Kaufmann, Discovering the
Universe, 8th ed.), Answer
·
· 1.
· only specific wavelengths of light will be removed from the
spectrum.
·
· 2.
· the atoms of the gas cloud will add energy to the overall
spectrum,
· enhancing it at specific wavelengths to produce emission
lines.
·
·
· 3.
· the whole spectrum will be reduced in intensity.
·
· 4.
· the cool gas will not affect the spectrum of the star because
cool atoms
· cannot absorb light.
·
1 points
Question 2
· In the revolution that overtook physics around 1900, the
assumption that Planck made in order to solve the problem
concerning the spectrum of radiation emitted by a hot blackbody
was that radiation was Answer
·
· 1.
· emitted in small, discrete packets or quanta of energy whose
individual

2. · energies were inversely proportional to the wavelength of the
light.
·
·
· 2.
· made up of small, discrete packets or quanta of energy whose
individual
· energies were all the same, independent of wavelength.
·
·
· 3.
· emitted as continuous waves whose wavelength was inversely
· proportional to the temperature of the object.
·
·
· 4.
· emitted in small, discrete packets or quanta of energy, each
quantum
· having an energy directly proportional to the wavelength of
the light.
·
1 points
Question 3
· The element helium was first discovered and identified as
a separate element Answer
·
· 1.
· inside meteorites that had come from outer space.
·
· 2.
· on the Sun, from the emitted spectrum from its upper
atmosphere.
·
· 3.
· in rocks containing radioactively decaying elements such as
uranium.

3. ·
· 4.
· in natural gas originating underground, from the spectrum
emitted
· from a flame of burning natural gas.
·
1 points
Question 4
· An atom in which one or more electrons has been removed
is known as a(n) Answer
·
· 1.
· molecule.
·
· 2.
· excited atom.
·
· 3.
· isotope.
·
· 4.
· ion.
·
1 points
Question 5
· A particular spectrograph, used by an astronomer to
disperse light into its colors, contains a piece of glass that has
been ruled with thousands of closely spaced, parallel lines.
What is the name of this piece of glass? Answer
·
· 1.
· CCD array
·
· 2.
· interferometer
·

4. · 3.
· diffraction grating
·
· 4.
· prism
·
1 points
Question 6
· To a physicist, a blackbody is defined as an object that
Answer
·
· 1.
· reflects all radiation that falls on it, never heating up and
always appearing black.
·
· 2.
· always emits the same spectrum of light, whatever its
temperature.
·
· 3.
· absorbs all radiation that falls on it.
·
· 4.
· always appears to be black, whatever its temperature.
·
1 points
Question 7
· A piece of iron is heated from 400 K to 800 K (127°C to
527°C). The total energy emitted per second by this iron will
increase by a factor of Answer
·
· 1.
· 296.5.

5. ·
· 2.
· 4.
·
· 3.
· 2.
·
· 4.
· 16.
·
1 points
Question 8
· The visible region of the spectrum ranges in wavelength
from about 400 nm to 700 nm. Which one of the following
photons is NOT in the visible range? Answer
·
· 1.
· 3.8 × 10–19 joules
·
· 2.
· 3.0 × 10–19 joules
·
· 3.
· 4.5 × 10–19 joules
·
· 4.
· 9.0 × 10–19 joules
·
1 points
Question 9
· The star P Cygni (in the constellation Cygnus, the Swan) is
surrounded by an extensive low-density atmosphere. It has a
bright, continuous spectrum with many narrow, dark absorption
lines and a few bright emission lines. The bright, continuous
part of the spectrum is produced by Answer
·

6. · 1.
· the low-density atmosphere of the star emitting light in all
directions.
·
· 2.
· the hot, dense, opaque gas of the star's surface.
·
· 3.
· only the part of the low-density atmosphere that is between
Earth
· and the surface of the star.
·
·
· 4.
· all parts of the star, the stellar surface, and the atmosphere,
equally.
·
1 points
Question 10
· Spectral lines are of particular importance in astronomy
because Answer
·
· 1.
· each different element has a characteristic line spectrum.
·
· 2.
· they are the only light bright enough to be seen over long
distances.
·
· 3.
· only stars produce bright line spectra.
·
· 4.
· they can be observed through a diffraction grating.