Download Phys133-Sample MT2

Phys133-Sample MT2
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) About what is the average temperature of the surface of the Sun?
A) 6,000 K
B) 10,000 K
C) 1 million K
D) 1,000 K
E) 100,000 K
1)
2) Why did the solar nebula heat up as it collapsed?
A) Radiation from other nearby stars that had formed earlier heated the nebula.
B) As the cloud shrank, its gravitational potential energy was converted to kinetic energy
and then into thermal energy.
C) Collisions among planetesimals generated friction and heat.
D) The shock wave from a nearby supernova heated the gas.
E) Nuclear fusion occurring in the core of the protosun produced energy that heated the
nebula.
2)
3) Cluster ages can be determined from
A) visual binaries.
B) pulsating variable stars.
C) spectroscopic binaries.
D) main sequence turnoff.
E) main sequence fitting.
3)
4) Where did the elements heavier than hydrogen and helium come from?
A) They were produced in the Big Bang.
B) They were produced inside stars.
C) They evolved from hydrogen and helium shortly after the Big Bang.
D) They were produced inside dense interstellar gas.
E) all of the above
4)
5) Suppose you measure the parallax angle for a particular star to be 0.01 arcsecond. The distance
to this star is
A) 100 light-years.
B) 0.01 light-year.
C) 0.01 parsec.
D) 100 parsecs.
E) impossible to determine.
5)
6) No stars have been found with masses greater than 200-300 times our Sun because
A) they would fragment into binary stars because of their rapid rotation.
B) they would generate so much power that they would blow themselves apart.
C) they are not bright enough to be seen nearby.
D) molecular clouds do not have enough material to form such massive stars.
E) they shine exclusively at X-ray wavelengths and become difficult to detect.
6)
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7) A star's luminosity is the
A) apparent brightness of the star in our sky.
B) total amount of light that the star radiates each second.
C) lifetime of the star.
D) surface temperature of the star.
E) total amount of light that the star will radiate over its entire lifetime.
8) Which of the following is closest in MASS to a white dwarf?
A) the Moon
B) Earth
C) the Sun
7)
8)
D) Jupiter
9) What is the basic definition of a black hole?
A) An object with gravity so strong that not even light can escape.
B) Any object made from dark matter.
C) A compact mass that emits no visible light.
D) A dead star that has faded from view.
9)
10) Compared to the star it evolved from, a red giant is
A) cooler and brighter.
B) hotter and brighter.
C) hotter and dimmer.
D) the same temperature and brightness.
E) cooler and dimmer.
10)
11) What happens when a star exhausts its core hydrogen supply?
A) Its core contracts, but its outer layers expand and the star becomes bigger but cooler and
therefore remains at the same brightness.
B) It contracts, becoming hotter and brighter.
C) It expands, becoming bigger but dimmer.
D) Its core contracts, but its outer layers expand and the star becomes bigger and brighter.
E) It contracts, becoming smaller and dimmer.
11)
12) After a massive-star supernova, what is left behind?
A) always a neutron star
B) either a neutron star or a black hole
C) either a white dwarf or a neutron star
D) always a black hole
E) always a white dwarf
12)
13) Which of the following sequences correctly describes the stages of life for a low-mass star?
A) protostar, main-sequence, red giant, white dwarf
B) protostar, main-sequence, white dwarf, red giant
C) red giant, protostar, main-sequence, white dwarf
D) protostar, red giant, main-sequence, white dwarf
E) white dwarf, main-sequence, red giant, protostar
13)
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14) What is the Sun made of?
A) 100 percent hydrogen and helium
B) 70 percent hydrogen, 28 percent helium, 2 percent other elements
C) 50 percent hydrogen, 25 percent helium, 25 percent other elements
D) 70 percent helium, 28 percent hydrogen, 2 percent other elements
E) 98 percent hydrogen, 2 percent helium and other elements
14)
Refer to the labels (a) through (e) on the following sketch of an H–R diagram. [Note that choice (a) refers to the entire main sequence,
while (c) and (d) refer to only small parts of the main sequence. If choices (c) or (d) offer better answers to the question than (a), use
the best choice.]
15) Which group represents stars that are extremely bright and emit most of their radiation as
ultraviolet light?
A) A
B) B
C) C
D) D
E) E
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