College Physics
2nd Edition
ISBN: 9780134601823
Author: ETKINA, Eugenia, Planinšič, G. (gorazd), Van Heuvelen, Alan
Publisher: Pearson,
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Chapter 25, Problem 41GP
To determine
The average density of the Milky Way galaxy by assuming that it contains about
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Astronomers are always seeking to build bigger, more powerful telescopes, which will allow them to study faint galaxies that are very far away. Which of the following is the main reason they're so obsessed with studying very distant galaxies?
Group of answer choices
Light traveled much faster during the early history of the universe, so we can study how the speed of light has changed through time.
Very distant galaxies are more likely to contain planets than the Milky Way is, so we have a better chance of detecting life in those galaxies than we do in our own galaxy.
Since the light from these galaxies took so long to reach us, we're seeing them as they were when the universe was very young.
Strangely, distant galaxies are more like our Milky Way than the Milky Way's `neighbor' galaxies are, and astronomers would like to figure out why this is.
The mass density of our universe is measured to be about 10-29 kg/m3. If an arbitrary point is chosen as the center, how large is the radius of a spherical surface centered at the point so that the mass enclosed in the surface will become a blackhole observed by someone outside the surface?
A. 4.2 trillion light years
B. 420 billion light years
C. 42 billion light years
D. 4.2 billion light years
Is the answer D? Thanks!
Part 1. Stellar Mass Black Holes
These are the collapsed cores of massive stars which end their life in supernova explosions. The
stellar core can no longer use nuclear fusion to hold up the immense gravity, and collapses until
its escape velocity rises higher than the speed of light. Voila! A black hole is formed.
Part A: The Schwarzschild Radius
The Schwarzschild Radius is defined as:
2GM
(1)
=
c2
where r, is the Schwarzschild radius, G is the gravitational constant, M is the mass of the black
hole, and c is the speed of light.
1. Let's say we have a black hole with a mass 10 times that of the Sun (the Sun's mass is 2 x
1030 kg, so the mass of the black hole is then 2 x 1031 kg). Using the definitions for G and
c, what would the Schwarzschild radius of this black hole be?
2. If the radius of the Sun is 7 x 108 m, how does the black hole's radius compare? (Divide
the radius of the Sun by the Schwarzschild radius). Your answer should be in the form of
times smaller/bigger than the…
Chapter 25 Solutions
College Physics
Ch. 25 - Review Question 25.1 What is the difference...Ch. 25 - Review Question 25.2 What needs to happen to...Ch. 25 - Review Question 25.3 How are GPS and radar...Ch. 25 - Review Question 25.4 If the frequency of one...Ch. 25 - Review Question 25.5 Electromagnetic waves are...Ch. 25 - Review Question 25.6 Explain why polarizing...Ch. 25 - Multiple Choice Questions The fact that light can...Ch. 25 - Multiple Choice Questions What does a beam of...Ch. 25 - Multiple Choice Questions What does Faraday's law...Ch. 25 - Multiple Choice Questions
4. Maxwell's hypothesis...
Ch. 25 - Multiple Choice Questions What does a simple...Ch. 25 - Multiple Choice Questions An electrically charged...Ch. 25 - Prob. 7MCQCh. 25 - Multiple Choice Questions If the amplitude of an E...Ch. 25 - Multiple Choice Questions
9. You notice that...Ch. 25 - Multiple Choice Questions You have two green...Ch. 25 - Prob. 11CQCh. 25 - Conceptual Questions What are two models that...Ch. 25 - Conceptual Questions
13. Summarize Maxwell's...Ch. 25 - Conceptual Questions What testable predictions...Ch. 25 - Conceptual Questions
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17. What determines the...Ch. 25 - Conceptual Questions How was the hypothesis that...Ch. 25 - Conceptual Questions
19. What is the difference...Ch. 25 - Conceptual Questions
20. How do polarized glasses...Ch. 25 - Conceptual Questions You bought a pair of glasses...Ch. 25 - Conceptual Questions Why. when we use polarized...Ch. 25 - Conceptual Questions 23 How does a polarizer for...Ch. 25 - Conceptual Questions
24. What is an LCD and how...Ch. 25 - Prob. 25CQCh. 25 - 25.1 and 25.2 Polarization of waves and Discovery...Ch. 25 - 25.1 and 25.2 Polarization of waves and Discovery...Ch. 25 - 25.1 and 25.2 Polarization of waves and Discovery...Ch. 25 - 25.1 and 25.2 Polarization of waves and Discovery...Ch. 25 - 25.1 and 25.2 Polarization of waves and Discovery...Ch. 25 - 25.1 and 25.2 Polarization of waves and Discovery...Ch. 25 - 25.1 and 25.2 Polarization of waves and Discovery...Ch. 25 - Prob. 8PCh. 25 - 25.1 and 25.2 Polarization of waves and Discovery...Ch. 25 - 25.1 and 25.2 Polarization of waves and Discovery...Ch. 25 - 25.3 Applications of electromagnetic waves 11 EST...Ch. 25 - 25.3 Applications of electromagnetic waves
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13. *...Ch. 25 - 25.3 Applications of electromagnetic waves *...Ch. 25 - 25.3 Applications of electromagnetic waves * TV...Ch. 25 - 25.3 Applications of electromagnetic waves **...Ch. 25 - 25.4 and 25.5 Frequency, wavelength, and the...Ch. 25 - Prob. 18PCh. 25 - 25.4 and 25.5 Frequency, wavelength, and the...Ch. 25 - 25.4 and 25.5 Frequency, wavelength, and the...Ch. 25 - 25.4 and 25.5 Frequency, wavelength, and the...Ch. 25 - 25.4 and 25.5 Frequency, wavelength, and the...Ch. 25 - 25.4 and 25.5 Frequency, wavelength, and the...Ch. 25 - 25.4 and 25.5 Frequency, wavelength, and the...Ch. 25 - Prob. 25PCh. 25 - 25.4 and 25.5 Frequency, wavelength, and the...Ch. 25 - 25.4 and 25.5 Frequency, wavelength, and the...Ch. 25 - Prob. 29PCh. 25 - 25.6 Polarization and light reflection
33. * An...Ch. 25 - 25.6 Polarization and light reflection * BIO...Ch. 25 - 25.6 Polarization and light reflection
35. * Two...Ch. 25 - 25.6 Polarization and light reflection * Light...Ch. 25 - Polarization and light reflection 37 * Light...Ch. 25 - 25.6 Polarization and light reflection
38.*...Ch. 25 - 25.6 Polarization and light reflection
40.* A beam...Ch. 25 - Prob. 41GPCh. 25 - * BIO EST Human vision power sensitivity A rod in...Ch. 25 - Prob. 44GPCh. 25 - Prob. 45GPCh. 25 - s experiment (described in Problem 25.45) the...Ch. 25 - * A sinusoidal electromagnetic wave in air has a...Ch. 25 - 48.* EST A microwave oven produces electromagnetic...Ch. 25 - with respect to the axis of the first polarizer....Ch. 25 - BIO Amazing honeybees The survival of a bee colony...Ch. 25 - BIO Amazing honeybees The survival of a bee...Ch. 25 - BIO Amazing honeybees The survival of a bee colony...Ch. 25 - BIO Amazing honeybees The survival of a bee colony...Ch. 25 - BIO Amazing honeybees The survival of a bee colony...Ch. 25 - Incandescent lightbulbs—soon to disappear ...Ch. 25 - BIO Amazing honeybees The survival of a bee colony...Ch. 25 - Incandescent lightbulbssoon to disappear Australia...Ch. 25 - Incandescent lightbulbs—soon to disappear ...Ch. 25 - Incandescent lightbulbs—soon to disappear...
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