A summary of the physical and chemical nature
of life must begin, not on the Earth, but in the Sun. in fact, at the Sun's
very center. It is here that is to be found the source of the energy that the
Sun constantly pours out into space as light and heat.
This energy is liberated at the center of the
Sun as billions upon billions of nuclei of hydrogen atoms collide with each
other and fuse together to form nuclei of helium. and, in doing so. release
some of the energy that is stored in the nuclei of atoms. The output of light
and heat of the Sun requires that some 600 million tons of hydrogen be
converted into helium in the Sun every second. This the Sun has been doing for
several thousands of millions of years.
The nuclear energy is released at the Sun's
center as high-energy gamma radiation, a form of electromagnetic radiation like
light and radio waves, only of very much shorter wavelength. This gamma
radiation is absorbed by atoms inside the Sun, to be re-emitted at slightly
longer wavelengths. This radiation, in its turn, is absorbed and re-emitted. As
the energy filters through the layers of the solar interior, it passes through
the x-ray part of the spectrum, eventually becoming light. At this sage, it has
reached what we cal: the solar surface, and can escape into space. without
being absorbed further by solar atoms. A very small fraction of the Sun' s
light and heat is emitted in such directions that, after passing unhindered
through inter-planetarv, space, It hits the Earth.
Questions
1. What does the passage mainly discuss?
(A) the production of solar light and heat
(B) the physical and chemical nature of life
(C) The conversion of hydrogen to helium
(D) Radiation in the x-ray part of the
spectrum
2. According to the passage, energy is
released in the Sun when
(A) helium atoms bind with each other
(B) gamma radiation escapes from the spectrum
(C) radiation is absorbed by helium
(D) nuclei of hydrogen atoms collide
3. The passage indicates that, in
comparison to radio waves, gamma waves
(A) produce louder sound
(B) are less magnetic
(C) do not form in the Sun's center
(D) are not as long
4. According to the passage, through which of
the following does the energy released in the Sun pass before it becomes light?
(A) The x-ray part of the spectrum
(B) Electromagnetic space
(C) The solar surface
(D) interplanetary space
5. It can be inferred from the passage that
the Sun's light travels
(A) through solid objects in space
(B) in many different directions
(C) more slowly than scientists previously
believed
(D) further in summer than in winter
Please tally your answer with the below provided answers and
then comment here how much you got!
Answers
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