BUCKNELL UNIVERSITY
Astronomy 101- Quiz #2
Name & Seat #: _______Key___ March 3, 2000
Formulas and numbers that you may need:
Energy = mass x c^2
Waves speed: v=f l; Period:
P=1/f
Photons energy: E=hf,
Doppler shift: Df/f=v/c
c = 3.0 x 108 m/s; h=6.6 x 10-34 J*s; 1 A.U.
= 1.5 x 10^11 meter
Intensity = Power/Area
Area of a sphere = 4 pi r^2; Volume of a sphere = (4/3)
pi r^3
From the observer’s triangle: Tan (alpha/2) = D/2L
Answer ALL 10 questions:
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A chunk of matter has a mass of 1kg. Assuming that all that
matter is converted into energy, the energy given off is:
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1 Joule
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3 x 10^8 Joule
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9 x 10^16 Joule
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1.5 x 10^11 Joule
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The strong force is
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A repulsive force between protons
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An attractive force between protons
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The force responsible for changing protons into neutrons
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An attractive force between all particles in the universe
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Plasma is a state of matter in which
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electrons are ionized from their "mother atoms"
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protons and neutrons change into electrons and neutrinos
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everything is a liquid, like water or blood plasma
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antimatter atoms kept in magnetic confinement
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Using the parallax method we may find
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the distance across a river
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the distance to the nearest stars
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the distance to a nearby planet
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all of the above
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Observing a star in spring and then in fall we find that
it moved 9.3 x 10-5 degrees with respect to faraway stars. The
distance to that star is roughly:
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100 000 A.U.
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10 thousand A.U.
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1 thousand A.U.
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1 million A.U.
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The distance to a star may be found if we know the star’s
power, and measure its intensity (same as brightness). The area in the
formula Intensity = Power/Area is just
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4pi x the distance to the star
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4pi x (the distance to the star)^2
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4pi x (the radius of the star)^2
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4pi x the radius of the star
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Stars form when gas clouds contract due to
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the strong force
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gravity
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coherent radiation from interstellar masers
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the pull between electrons and protons
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As the gas clouds that form stars contract they may
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become very cold, because of the decreased space they occupy
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become electrically charged, because only the protons fall
towards the middle
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spin faster and faster, possibly resulting in planet formation
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become red dwarfs
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When a converging (lentil shaped)lens is placed at roughly
the focal distance from a wall the image that you see is
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upside down and right side stays right
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upside down and right side on the left
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in black and white
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focused and right side up
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The three stars in "Orion’s belt" are
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white dwarfs
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all M2 stars
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at very different distances from earth
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oriented this way because they are a part of a triple star
system