Universe: Stars And Galaxies
6th Edition
ISBN: 9781319115098
Author: Roger Freedman, Robert Geller, William J. Kaufmann
Publisher: W. H. Freeman
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Chapter 5, Problem 32Q
To determine
The reason the ultraviolet rays with less than
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Voyager 2.
When the Voyager 2 spacecraft was approaching towards its Neptune encounter in
1989, it was 4.5 × 10° km away from the earth. Its radio transmitter, with which it
communicated with us (and we communicated with it), broadcast with a mere 22 Watt
of power at the S-band (2.1 GHz). (Your home wi-fi router emits around 2 Watt at 2.4
GHz wi-fi band). Assuming the Voyager transmitter broadcast equally in all directions,
(a) What signal intensity was received on the earth?
(b) What electric and magnetic field amplitudes were detected?
(c) How many 2.1 GHz photons were arriving per second on a radio-receiver antenna
with a circular cross-section of diameter 34 meters?
Two counter-propagating plane waves
(a) Let E(z, t) = E0 cos(kz – wt)â + E, cos(kz + wt)x. Write E(z, t) in simpler form
and find the associated magnetic field.
(b) For the fields in part (a), find the instantaneous and time-averaged electric and
magnetic field energy densities.
(c) Let E(z, t) = E, cos(kz – wt)x + E,…
2. Plasma oscillations in the ionosphere. The plasma density in the lower ionosphere has
been measured during satellite reentry to be about a) 10¹8 m-³ at 50 km altitude, b) 10¹7
m-³ at 70 km and c) 10¹4 m²³ at 85 km. Use the formula for the electron plasma
frequency to compute its numerical value for each of these three altitudes, AND state
(we'll address this quantitatively later, when we get to EM wave propagation in
plasmas) why the ionosphere is a relevant consideration for radio communications both
on earth and between earth and interplanetary spacecraft.
You have a radio telescope that you are designing to observe the fine details of the ring of hydrogen
around Jupiter (yes, Jupiter does have rings, but not as pretty as Saturn.) Jupiter is about 5.93E8 km
from Earth. If you are trying to observe gas structures the size of a small town (about 1.0 km across)
and the wavelength of hydrogen alpha is 656.28 nm, then what is the minimum diameter that you
would need to have for your telescope to resolve the needed details to Rayleigh criterion?
Chapter 5 Solutions
Universe: Stars And Galaxies
Ch. 5 - Prob. 1QCh. 5 - Prob. 2QCh. 5 - Prob. 3QCh. 5 - Prob. 4QCh. 5 - Prob. 5QCh. 5 - Prob. 6QCh. 5 - Prob. 7QCh. 5 - Prob. 8QCh. 5 - Prob. 9QCh. 5 - Prob. 10Q
Ch. 5 - Prob. 11QCh. 5 - Prob. 12QCh. 5 - Prob. 13QCh. 5 - Prob. 14QCh. 5 - Prob. 15QCh. 5 - Prob. 16QCh. 5 - Prob. 17QCh. 5 - Prob. 18QCh. 5 - Prob. 19QCh. 5 - Prob. 20QCh. 5 - Prob. 21QCh. 5 - Prob. 22QCh. 5 - Prob. 23QCh. 5 - Prob. 24QCh. 5 - Prob. 25QCh. 5 - Prob. 26QCh. 5 - Prob. 27QCh. 5 - Prob. 28QCh. 5 - Prob. 29QCh. 5 - Prob. 30QCh. 5 - Prob. 31QCh. 5 - Prob. 32QCh. 5 - Prob. 33QCh. 5 - Prob. 34QCh. 5 - Prob. 35QCh. 5 - Prob. 36QCh. 5 - Prob. 37QCh. 5 - Prob. 38QCh. 5 - Prob. 39QCh. 5 - Prob. 40QCh. 5 - Prob. 41QCh. 5 - Prob. 42QCh. 5 - Prob. 43QCh. 5 - Prob. 44QCh. 5 - Prob. 45QCh. 5 - Prob. 46QCh. 5 - Prob. 47QCh. 5 - Prob. 48QCh. 5 - Prob. 49QCh. 5 - Prob. 50QCh. 5 - Prob. 51Q
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