About twice every century, one of the massive stars

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About twice every century, one of the massive stars in
our galaxy blows itself apart in a supernova explosion
that sends massive quantities of radiation and matter into
pace and generates shock waves that sweep through the
(5) arms of the galaxy. The shock waves heat the interstellar
gas, evaporate small clouds, and compress larger ones to
the point at which they collapse under their own gravity
to form new stars. The general picture that has been
developed for the supernova explosion and its aftermath
(10) goes something like this. Throughout its evolution, a
star is much like a leaky balloon. It keeps its equilibrium
figure through a balance of internal pressure against the
tendency to collapse under its own weight. The pressure
is generated by nuclear reactions in the core of the star
(15) which must continually supply energy to balance the
energy that leaks out in the form of radiation. Eventu-
ally the nuclear fuel is exhausted, and the pressure drops
in the core. With nothing to hold it up, the matter in the
center of the star collapses inward, creating higher and
(20) higher densities and temperatures, until the nuclei and
electrons are fused into a superdense lump of matter
known as a neutron star.
As the overlying layers rain down on the surface of
the neutron star, the temperature rises, until with a
(25) blinding flash of radiation, the collapse is reversed. A
thermonuclear shock wave runs through the now
expanding stellar envelope, fusing lighter elements into
heavier ones and producing a brilliant visual outburst
that can be as intense as the light of 10 billion suns. The
(30) shell of matter thrown off by the explosion plows through
the surrounding gas, producing an expanding bubble of
hot gas, with gas temperatures in the millions of
degrees. This gas will emit most of its energy at X-ray
wavelengths, so it is not surprising that X-ray observato-
(35) ries have provided some of the most useful insights into
the nature of the supernova phenomenon. More than
twenty supernova remnants have now been detected in
X-ray studies.
Recent discoveries of meteorites with anomalous
(40) concentrations of certain isotopes indicate that a super-
nova might have precipitated the birth of our solar system
more than four and a half billion years ago. Although
the cloud that collapsed to form the Sun and the planets
was composed primarily of hydrogen and helium, it also
(45) contained carbon, nitrogen, and oxygen, elements essential
for life as we know it. Elements heavier than helium
are manufactured deep in the interior of stars and would,
for the most part, remain there if it were not for the
cataclysmic supernova explosions that blow giant stars
(50) apart. Additionally, supernovas produce clouds of high-
energy particles called cosmic rays. These high-energy
particles continually bombard the Earth and are respon-
sible for many of the genetic mutations that are the
driving force of the evolution of species.

1. Which of the following titles best describes the content of the passage?
(A) The Origins and Effects of Supernovas
(B) The Life and Death of Stars
(C) The Origins and Evolution of Life on Earth
(D) The Aftermath of a Supernova
(E) Violent Change in the Universe

2. According to the passage, we can expect a supernova to occur in our galaxy
(A) about twice each year
(B) hundreds of times each century
(C) about once every fifty years
(D) about once every other century
(E) about once every four to five billion years

3. According to the passage all of the following are true of supernovas EXCEPT that they
(A) are extremely bright
(B) are an explosion of some sort
(C) emit large quantities of X-rays
(D) result in the destruction of a neutron star
(E) are caused by the collision of large galaxies

4. The author employs which of the following to develop the first paragraph?
(A) Analogy
(B) Deduction
(C) Generalization
(D) Example
(E) Refutation

5. It can be inferred from the passage that the meteorites mentioned by the author at line 39
(A) contain dangerous concentrations of radioactive materials
(B) give off large quantities of X-rays
(C) include material not created in the normal development of our solar system
(D) are larger than the meteors normally found in a solar system like ours
(E) contain pieces of a supernova that occurred several billion years ago

6. The author implies that
(A) it is sometimes easier to detect supernovas by observation of the X-ray spectrum than by observation of visible wavelengths of light
(B) life on Earth is endangered by its constant exposure to radiation forces that are released by a supernova
(C) recently discovered meteorites indicate that the Earth and other planets of our solar system survived the explosion of a supernova several billion years ago
(D) lighter elements are formed from heavier elements during a supernova as the heavier elements are torn apart
(E) the core of a neutron star is composed largely of heavier elements such as carbon, nitrogen, and oxygen

7. According to the passage what is the first event in the sequence that leads to the occurrence of a supernova?
(A) An ordinary star begins to emit tremendous quantities of X-rays.
(B) A neutron star is enveloped by a superheated cloud of gas.
(C) An imbalance between light and heavy elements causes an ordinary star to collapse.
(D) A cloud of interstellar gas rich in carbon, nitrogen, and oxygen, collapses to form a neutron star.
(E) An ordinary star exhausts its supply of nuclear fuel and begins to collapse.

8. According to the passage a neutron star is
(A) a gaseous cloud containing heavy elements
(B) an intermediate stage between an ordinary star and a supernova
(C) the residue that is left by a supernova
(D) the core of an ordinary star that houses the thermonuclear reactions
(E) one of billions of meteors that are scattered across the galaxy by a supernova


9. The author is primarily concerned with
(A) speculating about the origins of our solar system
(B) presenting evidence proving the existence of supernovas
(C) discussing the nuclear reaction that occurs in the core of a star
(D) describing the sequence of scientific events
(E) disproving a theory about the causes of supernovas


My attempt:

1- A
2- C
3- E
4- C
5- A
6- D
7- B
8- B
9- D

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by shovan85 » Tue Jul 31, 2012 3:55 am
I do not agree with this answer of yours!! Rest all I got the same as those of yours.
jaiswalamrita wrote: Passage ...... er ones to
the point at which they collapse under their own gravity
to form new stars. The general picture that has been
developed for the supernova explosion and its aftermath
(10) goes something like this. Throughout its evolution, a
star is much like a leaky balloon. It keeps its equilibrium
figure through a balance of internal pressure against the
tendency to collapse under its own weight. The pressure
is generated by nuclear reactions in the core of the star
(15) which must continually supply energy to balance the
energy that leaks out in the form of radiation. Eventu-
ally the nuclear fuel is exhausted, and the pressure drops
in the core. With nothing to hold it up, the matter in the
center of the star collapses inward,
creating.....
7. According to the passage what is the first event in the sequence that leads to the occurrence of a supernova?
(A) An ordinary star begins to emit tremendous quantities of X-rays.
(B) A neutron star is enveloped by a superheated cloud of gas.
(C) An imbalance between light and heavy elements causes an ordinary star to collapse.
(D) A cloud of interstellar gas rich in carbon, nitrogen, and oxygen, collapses to form a neutron star.
(E) An ordinary star exhausts its supply of nuclear fuel and begins to collapse.
Can someone please help with below kind of problems?
4. The author employs which of the following to develop the first paragraph?
(A) Analogy
(B) Deduction
(C) Generalization
(D) Example
(E) Refutation
If the problem is Easy Respect it, if the problem is tough Attack it