1. Seismic ________ waves cannot propagate through the Earth's core, while seismic ________ waves can.
a) shear; pressure *
b) electromagnetic; shear
c) pressure; shear
d) tidal; pressure
e) shear; tidal
2. The theoretical resolution of a telescope in arc-seconds is given by
a = 2.5 x 10^-5 (lambda / D)
where lambda is the wavelength of the radiation in Angstroms and D is the diameter of the primary mirror or lens in meters. If we ________ the value of lambda while leaving D fixed, then the resolution angle a is ________
a) double; halved.
b) tripled; halved.
c) tripled; doubled.
d) double; doubled. *
e) cannot be determined from the information given
3. The theoretical resolution in arc-seconds for a radio telescope with a diameter D = 10^4 meters observing at a wavelength of 10^8 Angstroms is ________. This telescope would make observations with a resolution of ________ if it were located on the Moon's surface, and observations with a resolution of ________ if it were located on the Earth's surface.
a) 0.05 arc-seconds; 0.05 arc-seconds; 1 arc-second
b) 0.25 arc-seconds; 0.25 arc-seconds; 1 arc-second
c) 12.5 arc-seconds; 12.5 arc-seconds; 1 arc-second
d) 12.5 arc-seconds; 0.25 arc-seconds; 1 arc-second
e) 0.25 arc-seconds; 0.25 arc-seconds; 0.25 arc-seconds *
4. The theoretical resolution in arc-seconds for an optical telescope with a diameter D = 5 meters observing at a wavelength of 10^4 Angstroms is ________. This telescope would make observations with a resolution of ________ if it were located on the Moon's surface, and observations with a resolution of ________ if it were located on the Earth's surface.
a) 0.05 arc-seconds; 1 arc-second; 0.05 arc-seconds
b) 1 arc-second; 0.025 arc-seconds; 1 arc-second
c) 10 arc-seconds; 0.025 arc-seconds; 1 arc-second
d) 0.05 arc-seconds; 0.05 arc-seconds; 1 arc-second *
e) 1 arc-second; 1 arc-second; 1 arc-second
5. Interferometry is the process that uses two or more small telescopes separated by a large distance to
a) improve the resolution to that of a telescope with a size equal to the distance between the telescopes. *
b) measure the spectra of dim stars and planets.
c) improve the light gathering power to that of a telescope with a size equal to the distance between the telescopes.
d) improve the sensitivity of photographic plates.
6. Atmospheric blurring is due to
a) turbulent motions in the Earth's atmosphere *
b) radioactive decay
c) photon collisions
d) atomic annihilation
7. If the concentration of CO2 in a planet's atmosphere increases,
a) the surface temperature drops until heating balances cooling.
b) the CO2 must escape into space.
c) the planet explodes.
d) the surface temperature increases because the additional CO2 acts like an extra blanket. *
e) a solar eclipse occurs.
8. A hot, dense gas at high pressure produces
a) a continuous spectrum. *
b) an emission spectrum.
c) an absorption spectrum.
d) no spectrum.
9. Atoms can be excited as a result of ________.
a) collisions with other atoms
b) emission of radiation
c) absorption of radiation
d) all of the above
e) both (a) and (c) *
10. The energy values for the electronic excitation levels in an atom are determined by
a) the radiation absorbed by it.
b) the number of electrons in its orbitals.
c) the number of protons in its nucleus. *
d) none of the above.
11. A hot, thin gas produces ________. Emission and absorption lines can be broadened due to ________.
a) absorption lines; high temperature and strong rotation
b) emission lines; low temperature and slow rotation
c) emission lines; high temperature and strong rotation *
d) a continuum spectrum; strong gravity
e) absorption lines; strong gravity
12. We know that according to the Doppler formula, the observed wavelength lambda_observed for a spectral line is related to the emitted wavelength lambda_emitted by the formula
(lambda_observed / lambda_emitted) = 1 + (v / c)
where c = 3 x 10^10 cm per second is the speed of light and v is the velocity of recession. If the emitted and observed wavelengths of the lines are given by
lambda_observed = 5,360 Angstroms, lambda_emitted = 4,102 Angstroms
lambda_observed = 5,672 Angstroms, lambda_emitted = 4,341 Angstroms
lambda_observed = 6,352 Angstroms, lambda_emitted = 4,861 Angstroms
lambda_observed = 8,576 Angstroms, lambda_emitted = 6,563 Angstroms
then the velocity v equals
a) away from us; 9.2 x 10^9 cm per second *
b) towards us; 9.2 x 10^9 cm per second
c) towards us; 5.4 x 10^10 cm per second
d) towards us; 2.5 x 10^10 cm per second
e) away from us; 2.5 x 10^10 cm per second
13. The highest high tides occur when
a) the planets are all aligned.
b) the Earth, Moon and Sun form a right triangle.
c) the Earth, Moon and Sun form a square.
d) the Earth, Moon, and Sun form a line. *
14. The lowest high tides occur when
a) the planets are all aligned.
b) the Earth, Moon and Sun form a right triangle. *
c) the Earth, Moon and Sun form a square.
d) the Earth, Moon, and Sun form a line.
15. Uranium 238 has a half-life of about 4 billion years and decays into lead. How long will it take for 7/8 of the Uranium to change into lead?
a) 2 billion years
b) 4 billion years
c) 6 billion years
d) 8 billion years
e) 12 billion years *
16. If two planets with the same mass but different temperatures start off with the same amount of hydrogen gas in their atmospheres, then the ________ planet will retain ________ of its hydrogen than the ________ planet.
a) hotter; more; cooler
b) cooler; more; hotter
c) cooler; less; hotter
d) hotter; less; cooler
e) both (b) and (d) *
17. Radio astronomy can be performed
a) in poor weather.
b) during the day.
c) from the surface of the Earth.
d) at night.
e) all of the above *
18. X-ray and gamma-ray astronomy
a) can be performed only from the ground.
b) provide no useful information.
c) are performed using the Hubble Space Telescope.
d) can be performed only from space. *
e) all of the above
19. Most of the oxygen in Earth's current atmosphere was
a) created by plants. *
b) outgassed from volcanoes.
c) formed at the same time the Earth formed.
d) released from silicon dioxide.
e) bound into rocks after being absorbed by the oceans.
Use the following list for problems 20 and 21...
(i) small, dense, rocky, with solid surfaces
(ii) clustered close to the Sun and each other
(iii) large and gaseous, with no solid surfaces
(iv) spread throughout the outer solar system
(v) weak magnetic fields, slow rotation
(vi) strong magnetic fields, rapid rotation
20. Which of the items on the list apply to the terrestrial planets?
a) (i), (ii), (iii)
b) (i), (iii), (v)
c) (i), (v), (vi)
d) (i), (ii), (v) *
e) None of the items on the list apply to the terrestrial planets.
21. Which of the items on the list apply to the Jovian planets?
a) (iii), (iv), (vi) *
b) (i), (ii), (iii)
c) (ii), (iv), (vii)
d) (i), (iii), (vi)
e) None of the items on the list apply to the Jovian planets.
22. We do not detect shear waves on the side of the Earth opposite from an earthquake. From this evidence we can deduce that
a) the Earth has a hollow center.
b) the Earth is composed mainly of light elements like hydrogen.
c) the Earth has the same density throughout the interior.
d) there is a solid core in the Earth.
e) there is a liquid core in the Earth. *
23. Consider two telescopes, one with a 3 inch diameter and one with a 15 inch diameter. The 15 inch telescope receives ________ times more light energy per second than the 3 inch telescope.
a) 1/25
b) 9
c) 1/9
d) 25 *
e) 10
Use the following list for problems 24 and 25...
(i) Searches for periodic Doppler shifts of lines in the spectrum of the central star.
(ii) Searches for periodic changes in the pulsations observed from a pulsar
(iii) Searches for planets with satellites in orbit around them.
(iv) Searches for periodic drops in the light from the central star due to transits by a planet.
(v) Searches for perodic, bright flashes from the central star.
(vi) Searches for supernova explosions.
24. Which methods on the list can be used to detect extra-solar planets?
a) (ii), (iii), (iv)
b) (i), (ii), (iv) *
c) (i), (v), (vi)
d) (i), (ii), (v)
e) None of the methods on the list can be used.
25. Which methods on the list have been used to detect planets with masses similar to that of the Earth?
a) (ii), (iv) *
b) (i), (iii), (v)
c) (i), (v), (vi)
d) (iii), (iv), (v)
e) None of the methods on the list can be used.
26. When white light is passed through a cool, thin gas, the photons that are absorbed
a) cause collisional excitation.
b) are re-emitted in the same direction they were originally moving in.
c) cause radiative excitation.
d) are re-emitted in random directions.
e) both (c) and (d) *
27. Most of the hydrogen in Earth's early atmosphere has
a) escaped into space. *
b) been absorbed by animals.
c) been removed by aliens.
d) been used by plants.
e) been bound into rocks or absorbed by the oceans.
28. Most large telescopes are reflectors and not refractors because
a) large lenses are difficult to support.
b) large lenses are difficult to fabricate.
c) large lenses suffer from chromatic aberration.
d) all of the above *
29. Based on the best available evidence, the amount of CO2 in the Earth's atmosphere seems to be
a) decreasing continuously over the last 100 years, mainly due to pollution, and ocean damage.
b) remaining the same.
c) increasing over the last 100 years, due to air pollution, destruction of rain forest, and ocean damage. *
d) rising and falling by a factor of 10 every year.
e) unmeasurable.
30. The ________ force causes hurricanes to spin ________ in the Northern hemisphere.
a) coriolis; clockwise
b) coriolis; counterclockwise *
c) gravitational; clockwise
d) gravitational; counterclockwise
e) none of the above