Reference no: EM131394506
Q1. A particular experiment (no magnetic field present) involves an electric discharge through helium gas at a pressure and temperature of 1 Torr (133.2 Pa) and 298 K respectively. The discharge is contained in a long, slender tube, so that any diffusion of electrons can be assumed primarily radial, and any electric field driven motion is primarily axial, resulting in a current between the electrodes. A luminous region of this discharge, called the "positive column," contains electrons with a temperature of Te = 2 eV. The electron-neutral collision cross section for 2 eV electrons in He is about 6πao2, where ao = 0.53⋅10-8 cm is the radius of the first Bohr orbit of the hydrogen atom.
a) Compute the electron diffusion coefficient in m2s-1 assuming that (σV), averaged over the electron velocity distribution, is just equal to σVe, where Ve is the velocity the electrons would have if accelerated to a kinetic energy of 2 eV.
b) If the current density in the column is J = 2 kA/m2 and the plasma density is 1016 m-3, what is the electric field along the column?
Q2. A common plasma probe design involves the use of a small piece of exposed wire. For this problem, assume the probe geometry is a cylinder of diameter d = 2 mm and exposed length L = 5 mm. The probe collects plasma from the exposed sides and tip. The probe is immersed in a xenon plasma with electron temperature of 3.5 eV. The xenon ion mass is mi = 2.18⋅10-25 kg.
a) If the probe collects 1 mA of ion current, what is the plasma density?
b) Two characteristic sizes for this experiment are the probe radius (for the probe) and the Debye length (for the sheath). Based on these two characteristic sizes, do you think the sheath can be considered "thin" with respect to the probe? Justify your answer.
c) If the probe is at the plasma potential, what is the electron current collected?
d) If the probe is at the floating potential, what is the electron current collected?
e) If the probe is at the floating potential, what is the ion current collected?
Attachment:- Assignment File.rar
|
Display given results in a bar graph
: How could the number of people who do not know who Martha Stewart is increase from June to July? Did people forget her? Or is the poll perhaps flawed? Explain how these results could be valid.
|
|
Identify new entrant or product that brings new competition
: Research and select an industry that you have not analyzed previously in this course. Within this industry, you should be able to identify a new entrant or product that brings new competition to the market because of emerging trends or changing tr..
|
|
What percent of people surveyed were republicans
: What percent of people surveyed were Republicans?- Do you think this might be a reasonable estimate of the percentage of all voters who are Republicans? Explain.
|
|
Discuss how the route of exposure can affect the toxicity
: Describe how toxicant absorption is limited for inhalation, absorption, and ingestion. Use an example of any drug or chemical, discuss how the route of exposure can affect the toxicity.
|
|
Compute the electron diffusion coefficient
: Compute the electron diffusion coefficient in m2s-1 assuming that (σV), averaged over the electron velocity distribution, is just equal to σVe, where Ve is the velocity the electrons would have if accelerated to a kinetic energy of 2 eV
|
|
What percent of people surveyed were republicans
: What percent of people surveyed were Republicans?- Do you think this might be a reasonable estimate of the percentage of all voters who are Republicans? Explain.
|
|
Are wage distributions likely to be symmetric or skewed left
: By contrast, for General and Operations Managers, the mean hourly wage was $47.73 and the median was $40.97. Are these wage distributions likely to be symmetric, skewed left, or skewed right? Explain.
|
|
What should the policies or laws regulate or encourage
: What should these policies or laws regulate or encourage? Use specific facts to defend your position. Has the law improved the environment or situation?
|
|
Identify the ws of given data
: Identify the W's of these data.- Identify the variables, classify each as categorical or quantitative, and specify units if relevant.
|