TELESCOPES AND INSTRUMENTS
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You observe a star through a 10-inch telescope on Earth.  Your
identical twin observes the same star from 3 times farther away.  How
big a telescope does your twin need to make the star appear as bright
as it does to you? 
    a) 5 inches
    b) 10 inches
   $c) 30 inches
    d) 90 inches
  
A telecope's sensitivity (light gathering power) is determined
primarily by its 
    a) objective diameter
   $b) objective area
    c) magnification
    d) objective focal length
    e) spatial resolution

The diameter of the objective of telescope 1 is D. The diameter of 
the objective of telescope 2 is 2D. The light gathering power of 
telescope 2 is ___ times the light gathering power of telescope 1.
   a) 1
   b) 2
   c) 3
  $d) 4

A telescope's spatial resolution is determined primarily by its
   $a)  objective diameter
    b)  objective area
    c)  magnification
    d)  objective focal length
    e)  spatial resolution

One disadvantage of a refracting telescope compared
with a reflector of the same diameter is that
    a)  refractors bend the light more
   $b)  refractors focus light of different wavelengths at different locations 
    c)  the refractor has a lower magnification
    d)  refractors have poor spatial resolution

Which of the following are problems with large refracting telescopes? 
    a) Weight.
    b) Chromatic aberration.
    c) Sagging of the objective.
    d) Both a and c.
   $e) All of the above.

The Keck telescope on Mauna Kea has a diameter of 10m compared
to 5m for the Palomar telescope.  The light gathering power
of the Keck is larger by a factor of
    a)  2
   $b)  4
    c)  15
    d)  50

One of the Gemini telescopes has 4 times the light gathering power of
the 4m telescope on Kitt Peak. How much farther into space can a
Gemini telescope detect a faint object?
    a)  distance does not depend on light gathering power
   $b)  2
    c)  4
    d)  8
    e)  16

The reason astronomers use telescopes in space is because
the Earth's atmosphere
    a) absorbs or scatters some of the light at all wavelengths.
    b) absorbs all of the light at some wavelengths.
    c) distorts images of astronomical objects.
   $d) All of the above.

The main reason astronomers use large telescopes is that large telescopes
    a) have a bigger field of view.
    b) have a larger magnification.
   $c) gather more light.
    d) None of the above.

Which of the following has never been seen since the invention of the 
telescope, and probably does not require a telescope to be detected?
    a) an individual star in another galaxy
    b) a change in the dark spot on Neptune
    c) a comet striking a planet
    $d) a supernova exploding in our galaxy

Light is refracted when passing through a lens because
   a)  light is absorbed by the surface of the lens and then
re-radiated in a different direction.
  $b) light moves at different speeds in the glass than it
does in air.
   c)  the wavelength changes when the light strikes the glass
which causes a bending of the wave.
   d)  internal reflections caused by atoms in the lens deflect the
light rays.

You are looking at a wall clock through a simple telescope    
objective lens.  Which number will be at the bottom of the image
formed in the focal plane of the lens?  
   $a) 12
    b) 3
    c) 6
    d) 9
                     
Telescopes have motors (clock drives) to track the stars across the
sky because the
    a) stars have proper motions
    b) Earth moves in its orbit
   $c) Earth spins on its axis
    d) Sun moves in its orbit

Temperature differences between the primary mirror of a       
telescope and the surrounding air cause 
    a) color distortions due to heat
    b) image blurring due to temperature-related focus changes
    c) image blurring due to buckling of the mirror surface
   $d) image blurring due to air turbulence

Which of the following combinations of focal lengths
for the objective/eyepiece would have the LOWEST magnifying power?
    a) long/long 
    b) long/short 
   $c) short/long 
    d) short/short 

The larger of 2 radio telescopes will collect
    a) less energy, and have greater resolving power.
    b) less energy, and have less resolving power.
   $c) more energy, and have greater resolving power.
    d) more energy, and have less resolving power.
    e) the same energy, and have the same resolving power.

Which of the following cannot be determined using radar?
   a) size
  $b) mass
   c) roughness
   d) distance
   e) velocity