Why Can't I Get the Same Answer for the Boltzmann Equation Problem?

In summary, the conversation discusses the equation for calculating the relative number of atoms in ground and excited states, using the example of sodium atoms in the 3s and 3p states at different temperatures. The solution shows the calculation steps using the values provided, but the person is having trouble getting the same result and suggests possible issues with entering the values or understanding the notation.
  • #1
atsum
9
0
Why I can't calculate the same answer as the solution below? I use the value as what the below solution showed.

Q:
Where Nj is the number of atoms in excited state, No is the number of atoms in the
ground state, Pj and Po are constants determined by the number of states having equal
energy at each quantum level, Ej is the energy difference between excited and ground
states, K is the Boltzmann constant, and T is the absolute temperature. To understand
the application of this equation let us consider the situation of sodium atoms in the 3s
state (Po = 2) when excited to the 3p excited state (Pj = 6) at two different
temperatures 2500 and 2510K. Now let us apply the equation to calculate the relative
number of atoms in the ground and excited states:
Usually we use the average of the emission lines from the 3p to 3s where we have two
lines at 589.0 and 589.6 nm which is:

Solution:
λ = (589.0+589.6)/2 = 589.3 nm
Ej = hc/λ
Ej = (6.6256x10-34 J s x 2.998x1010 cm s-1)/{(589.3 nm x (cm/ 107 nm)}
Ej = 3.37x10-19 J
Nj/No = (6/2) exp {(-3.37x10-19 J/(1.38x10-23 J K-1 x 2500 K)}
Nj/No = 1.72x10-4
 
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  • #2
atsum said:
Why I can't calculate the same answer as the solution below? I use the value as what the below solution showed.

Solution:
λ = (589.0+589.6)/2 = 589.3 nm
Ej = hc/λ
Ej = (6.6256x10-34 J s x 2.998x1010 cm s-1)/{(589.3 nm x (cm/ 107 nm)}
Ej = 3.37x10-19 J
Nj/No = (6/2) exp {(-3.37x10-19 J/(1.38x10-23 J K-1 x 2500 K)}
Nj/No = 1.72x10-4

Hard to tell where your problem is, calculations look correct and I got the same result from these numbers. Perhaps you are keying them wrong into calculator, or misunderstanding the notation. 2.998x1010 means 2.998x1010 and probably should be entered as 2.998e10 or something like that - details will depend on what (program, calculator model) you use.
 

FAQ: Why Can't I Get the Same Answer for the Boltzmann Equation Problem?

What is the Boltzmann equation problem?

The Boltzmann equation problem, also known as the Boltzmann transport equation, is a mathematical equation that describes the evolution of a system of particles in a gas or plasma. It is used to study the dynamics of a system at a microscopic level, taking into account interactions between particles and external forces.

What are the applications of the Boltzmann equation problem?

The Boltzmann equation problem has many applications in physics, chemistry, and engineering. It is commonly used to study the behavior of gases, plasmas, and fluids, and has applications in fields such as astrophysics, atmospheric science, and semiconductor device modeling.

What is the significance of the Boltzmann equation problem?

The Boltzmann equation problem is significant because it provides a fundamental understanding of how particles in a system behave and interact with each other. It allows scientists to make predictions about the behavior of complex systems at a microscopic level, which can have practical applications in various fields.

What are the challenges in solving the Boltzmann equation problem?

Solving the Boltzmann equation problem is a difficult task due to its highly nonlinear nature and the large number of variables involved. Additionally, the interactions between particles can be complex and difficult to model accurately. As a result, numerical methods and approximations are often used to solve the equation.

How is the Boltzmann equation problem related to statistical mechanics?

The Boltzmann equation problem is closely related to statistical mechanics, which is the branch of physics that studies the behavior of systems with a large number of particles. The Boltzmann equation is derived from statistical mechanics principles and is used to calculate macroscopic quantities such as temperature, pressure, and diffusion coefficients.

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