{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

ee 4 - EE 4770 Lecture Notes Generated from file lsli07.dvi...

Info icon This preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
EE 4770 Lecture Notes Generated from file lsli07.dvi. This page was generated using an imperfect translator. Text may be poorly positioned and mathematics will be barely readable. Illustrations will not show at all. If possible, view the PostScript or PDF versions of these notes. 07-1 Temperature 07* *-1 Definition: The translational (e.g., wiggling around) energy : : : : : :of particles in a system. No practical way to measure : : : : : :velocity of every particle : : : : : :in most systems of interest. Instead, temperature scales are defined. There are two types: - The thermodynamic temperature scale. "Really" measures temperature. - Practical temperature scales. Approximations of thermodynamic scale. Much easier to measure temperature on a practical scale. For temperatures of interest, differences are very small. 07-1 EE 4770 Lecture Transparency. Formatted 8:22, 27 January 1999 from lsli07. * * 07-1 07-2 07* *-2 Kelvin's Thermodynamic_________ Temperature Scale
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Due to William Thomson, a.k.a., Lord Kelvin (1824-1907). Start with a precise temperature that can easily be reproduced. The triple point of water, Ttr, is used. Ttr is temperature at which : : : : : :water can simultaneously be in : : : : : :the solid, liquid, and gas states: 0:01 ffiC. - Confine an ideal gas in a container of fixed volume, S. - Bring the gas to temperature Ttr. Call the pressure of this gas Ptr. By_definition___ (of the Kelvin scale) this temperature is Ttr , 273:16 K. The ideal gas law: P S = n< = ___PtrS____273:16.K - Bring the same system to another temperature, T . Call the pressure at this temperature, P . Solving for T in the gas law: T = P_S_n<. Substituting for n< using the quantity obtained above yields T = P S 273:16_K___P= 273:16 K P___: trS Ptr 07-2 EE 4770 Lecture Transparency. Formatted 8:22, 27 January 1999 from lsli07. * * 07-2 07-3 07* *-3 Practical Temperature Scales_ Designed to be easy (relatively) to measure.
Image of page 2
Scales are revised every few decades. Latest revision in 1990, called ITS-90. (International Temperature Scale.) Older scale (1968), IPTS-68. (International Practical Temperature Scale) Difference between ITS-90 and IPTS-68 : : : : : :is as large as 0:4 ffiCat 800 ffiC. At human-tolerable temperatures, : : : : : :difference is in hundreths of a degree. All practical scales are identical at the triple point of water. How a practical temperature scale is defined: A set of fixed points is established, : : : : : :for example the triple point of water. A temperature is assigned to each fixed point, : : : : : :based on the thermodynamic scale. Accurate thermometers (transducers) are chosen. Functions are defined mapping : : : : : :the thermometers' output to temperature : : : : : :so that they pass through the fixed points. ) Temperatures defined in terms of fixed points and special transducers. 07-3 EE 4770 Lecture Transparency. Formatted 8:22, 27 January 1999 from lsli07. * * 07-3 07-4 07* *-4 For ITS-90: - (:65 K; 5:0 K) Vapor-pressure relation between two isotopes of helium.
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
- (3:0 K; 24:5561 K) Helium fixed-volume thermometer.
Image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern