Need to know what the K stands for in this equation

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Discussion Overview

The discussion revolves around the identification of the constant 'k' in the equation for calculating the Root Mean Squared speed of a molecular gas, specifically in the context of temperature and molecular mass. The scope includes conceptual clarification and technical explanation related to thermodynamics and kinetic theory.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant inquires whether 'k' in the equation for RMS speed is the Boltzmann constant, suggesting they are experiencing unexpected results in their calculations.
  • Several participants confirm that 'k' is indeed the Boltzmann constant, provided the context involves the RMS speed of a molecular gas at temperature T with molecular mass m.
  • Another participant emphasizes the importance of using the absolute temperature scale (Kelvin) in calculations.
  • There is a suggestion to ensure proper use of parentheses in the calculation to avoid errors in determining the radicands.

Areas of Agreement / Disagreement

Participants generally agree that 'k' refers to the Boltzmann constant in the specified context, but the discussion includes uncertainty regarding the participant's calculations and the proper use of temperature scales and mathematical notation.

Contextual Notes

There are limitations regarding the assumptions made about the context of the equation, such as the specific conditions under which the RMS speed is calculated and the potential for errors in mathematical execution.

LocalStudent
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I'm busy solving a physics question and I am getting unexpected results.

I just want to check if I am using the right constant in this equation:
I am using the equation to find the Root Mean Squared speed = √(8/3∏) √3kT/m

Is k in this equation the Boltzmann constant? (1.4e-23)
 
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Yes it is. (As long as you are indeed talking about the RMS speed of a molecular gas or some such at temperature T with molecular mass m)
 
Matterwave said:
Yes it is. (As long as you are indeed talking about the RMS speed of a molecular gas or some such at temperature T with molecular mass m)

Thanks. Then I must be going wrong somewhere else.. I'm sure I'll find it. Thanks again
 
T is in Kelvin, is that the temperature scale you have used?
 
Make sure your temperature is in absolute scale (e.g. Kelvin), not degrees.
 
I've used kelvin. And mass in kilograms.

Thanks for the input. I'll post the actual question later and you could see if I've done it correctly or not.
 
Have you been careful and told your calculator what the correct radicands are? That is, have you used parantheses around the full expression that should stand under the square root signs?
 

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