Practice Questions Electromagnetic Spectrum
Practice QuestionsElectromagnetic Spectrum
The electromagnetic spectrumFigure 3.5
Identify the following portions of theElectromagnetic spectrum:
A B D EC
The electromagnetic spectrumFigure 3.5
Which end of the spectrum is more energetic, A or B? Why?
A B
Light has a DUAL NATURE!
“photon”wave
&
If the Hydrogen
gas cloud is moving towards
Earth, the absorption line marked will shift in
which direction?
BA
An absorption line of Hydrogen measured at rest
How do light and matter interact?KNOW THESE DEFINITIONS!
• Emission
• Absorption
• Transmission
• Reflection or Scattering
What types of light spectra can we observe?
1. Continuous spectra
2. Absorption spectra
3. Emission spectra
Which is the absorption spectrum?
Which is the continuous spectrum?
Which is the emission spectrum?
BLUE
Yellow
RED
BLACK
Which spectrum is coming from the coolest object?
BLUE
Yellow
RED
BLACK
The object producing the yellow spectrum might be what type of star?
BLUE
Yellow
RED
BLACK
Is the star producing the yellow or red spectrum hotter? Why?
BLUE
Yellow
RED
BLACK
Which spectrum is coming from the hottest object?
Which star is more luminous?
T = 15,000 KRadius = 1 unit T = 15,000 K
Radius = 2 units
Which star is more luminous?
T = 3,000 KRadius = 1 unit
T = 15,000 KRadius = 1 unit
REMEMBER!
Luminosity of a star is intrinsic.
Depends on Temperature & Radius.
For which stars would we observe a Doppler Shift?
A
B
C
Doppler shiftFigure 3.18
Doppler Effect Summary
Motion toward or away from an observer causes a
shift in the observed wavelength of light:
• blueshift (shorter wavelength)
motion _______ you
• redshift (longer wavelength) motion AWAY
from you
• greater shift greater speed
Doppler Effect Summary
Motion toward or away from an observer causes a
shift in the observed wavelength of light:
• blueshift (shorter wavelength) motion toward
you
• redshift (longer wavelength)
motion ______ from you
• greater shift greater speed
How do telescopes help us learn about the universe?
• Telescopes collect more light than our eyes
light-collecting area
• Telescopes can see more detail than our eyes angular resolution
• Telescopes/instruments can detect light that is invisible to our eyes (e.g., infrared, ultraviolet)
The energy source for the sun is
• A. combustion of hydrocarbons
• B. solar flares
• C. nuclear fission, the splitting of two
hydrogen atoms
• D. nuclear fusion, the joining of two
hydrogen atoms
• E. combustion of hydrogen
The energy source for the sun is
• A. combustion of hydrocarbons
• B. solar flares
• C. nuclear fission, the splitting of two
hydrogen atoms
• D. nuclear fusion, the joining of two
hydrogen atoms
• E. combustion of hydrogen
The hotter an object
• A. the brighter it appears at all wavelengths, and the longer the wavelength at which it appears brightest• B. the shorter the wavelength at which it appears brightest• C. The brighter it appears at all wavelengths, and the shorter the wavelength at which it appears brightest• D. the longer the wavelength at which it appears brightest• E. the brighter it appears at all wavelengths
The hotter an object
• A. the brighter it appears at all wavelengths, and the longer the wavelength at which it appears brightest• B. the shorter the wavelength at which it appears brightest• C. The brighter it appears at all wavelengths, and the shorter the wavelength at which it appears brightest• D. the longer the wavelength at which it appears brightest• E. the brighter it appears at all wavelengths
An object emits an emission line spectrum. If the object moves towards
an observer,• A. the observed emission lines shift to
shorter wavelengths
• B. the observed emission lines shift to longer
wavelengths
• C. the emission line spectrum shifts to a
continuous spectrum
• D. the emission line spectrum shifts to
an absorption line spectrum
An object emits an emission line spectrum. If the object moves towards
an observer,• A. the observed emission lines shift to
shorter wavelengths
• B. the observed emission lines shift to longer
wavelengths
• C. the emission line spectrum shifts to a
continuous spectrum
• D. the emission line spectrum shifts to
an absorption line spectrum
Which of the following is ordered by increasing wavelength?
• A. infrared, visible, radio, gamma-ray
• B. visible, infrared, radio, gamma-ray
• C. gamma-ray, visible, infrared, radio
• D. radio, visible, infrared, gamma-ray
Which of the following is ordered by increasing wavelength?
• A. infrared, visible, radio, gamma-ray
• B. visible, infrared, radio, gamma-ray
• C. gamma-ray, visible, infrared, radio
• D. radio, visible, infrared, gamma-ray
An atom is ionized if
• A. it has lost a proton
• B. it has lost an electron
• C. it has lost a neutron
• D. it has absorbed a photon
An atom is ionized if
• A. it has lost a proton
• B. it has lost an electron
• C. it has lost a neutron
• D. it has absorbed a photon