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Computation with Boltzman constant

Posted 13 days ago

Hi, I'm trying to run some calculations which includes the Boltzman constant but I'm getting some errors. I'm also attempting with the Quantity["BoltzmannConstant"] but not sure how to use it within the these simple equations. Any help will be greatly appreciated.


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Sorry, I forgot something else, these variables would be well defined ?: Thanks

La = Quantity[3 x 10^10, 1/"Centimeters"^2 * "Seconds"];
\[Sigma] = Quantity[2.02 x 10^-18, 1/"Centimeters"^2]^ ;
nNO = Quantity[1 x 10^8, 1/"Centimeters"^3];
deltaz = Quantity[900, "Kilometers"];
H = Quantity[10, "Kilometers"];
k = Quantity[3.5 x 10^-7, 1/"Centimeters"^3];
ne = Quantity[ 5.23 x 10^5, 1/"Centimeters"^3];
ni = Quantity [5.09 x 10^5, 1/"Centimeters"^3];
Posted 12 days ago

σ looks wrong, there is an extra ^ at the end. Also x does not represent multiplication, use *. I am not sure what you are calculating so I cannot say if it is right or wrong. Check the dimensions of Hp is that what you expect? For g you can use

g = Quantity[1, "StandardAccelerationOfGravity"]
POSTED BY: Rohit Namjoshi

Thanks so much. It is totally clear. Another quick question. Could you tell me if this approach could be right for this calculation: Any help will be appreciated. Thanks

Ti = Quantity[1200, "Kelvins"];
 Te = Quantity[3500, "Kelvins"];
kb = Quantity[1, "BoltzmannConstant"];
me = Quantity[1,  "ElectronMass"];
g = Quantity[9.8, "Meter"/"Seconds"^2];
mi = Quantity[2.656`*^-26, "Kilograms"]
Hp = kb* (Ti + Te)/mi * g 

Posted 13 days ago

You have to use Quantity to specify units. m^2 is not meters squared, it is the symbol m squared, and m is used on the left hand of Set. This is the equivalent to evaluating zz = zz + 1 which will result in recursion. Try

P = Quantity[0.18, "Pascals"];
\[Rho] = Quantity[88.7 , 1/"Centimeters"^3];
T = Quantity[190, "Kelvins"];
kb = Quantity[1, "BoltzmannConstant"];

m = kb*\[Rho]/P*T
(* 1.292670978*10^-12 *)
POSTED BY: Rohit Namjoshi
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