Download Answer Key 2

Answers for Practice Exam No. 2
Referents:
What do the following words refer to?
1. Line 4, their the stars’.
2. Line 6, it the cloud of gas.
3. Line 18, this the enrichment of the space with heavy elements.
4. Line 23, these objects planetary nebulae
5. Line 38, that the side
Comprehension Questions:
The correct answers are bolded and the justifications are underlined.
1. There is an inverse relationship between the mass of a star and
the length of its life. True/False
lines 1-2 The most massive stars live short lives.
2. The cloud of gas which is created in the supernova explosion
a. gradually decreases in size.
b. remains luminous for a thousand years.
c. is a product of thermonuclear fuel. (line 4)
d. is hotter than the central part of the dying star.
3. There is little variety in the dimensions of the planetary nebulae.
True/False
lines 9-10 Planetary nebulae have a spectacular array of
shapes, sizes and structures.
4. Carbon, nitrogen and oxygen are heavy elements, which
accounts for their stable position in the core of the star.
True/False
lines 12-13 Some of the heavy elements, e.g. carbon, nitrogen
and oxygen move into the star’s outer layers.
5. Investigation of the planetary nebulae has been made difficult
by
a. The lack of powerful equipment.
b. the intense glow of the surface.
c. excessive brightness of these objects.
d. the dispersion of the light over vast areas.
6. Circle True or False before each of the following completions.
No justification is necessary.
It follows from paragraph 4 (lines 27-33) that W.Herschel
a. was the first to use the term planetary nebulae.
True/False
b. noticed the resemblance between stars and planetary
nebulae. True/False
c. made mistaken assumptions about the origin of the
planetary nebulae. True/False
d. systematically arranged the data obtained from the
observations of planetary nebulae. True/False
e. published the results of his research towards the end of
the 17th century. True/False
7. The modern approach to the origin of planetary nebulae was
formed at the beginning of the 20th century. True/False
lines 40-42 It was only in 1956 that the Soviet astrophysicist
I.S. Shklovsky established the modern view that nebulae
represent the end of the stellar life cycle.
8. The rate of the planetary growth reaches up to 20 kilometers per
second. True/False
lines 45-46 The average rate of expansion of a planetary
nebula is 20 kilometers per second.
9. To determine the approximate age of a planetary nebula it is
sufficient to know its size and location. True/False
lines 48-49 A nebula’s age can be calculated on the basis of
its size and rate of expansion.
Words in Context:
What do the following words mean in the context of the article?
1. SWELL, line 4
a. a protuberant part.
b. to enlarge in bulk.
c. to grow in amount, degree, force.
2. MATTER, line 18
a. occasion.
b. importance.
c. physical substance.
d. material for thought.
3. DISTINCTIVE, line 35
a. famous.
b. separate.
c. characteristic.