- #1
rayman123
- 152
- 0
b]1. Homework Statement
[/b]
Table 8.6 shows the relative masses of the electron and a number of light atoms is derived from the values of the Rydberg constant (I have uploaded the table)
http://img833.imageshack.us/img833/645/namnlssm.jpg
Turn the problem around and use the data inte last column [tex] \lambda_{12}[/tex] (means) to find the mass of the electron given that the mass of the atoms are exact multiples of the unit mass [tex] 1.66\cdot10^{-27}kg[/tex]
I have started with calculating the Rydberg constant and used the formula
[tex] \frac{1}{\lambda}=R \cdotZ^2(\frac{1}{(n_{1})^2}-\frac{1}{(n_{2})^2})[/tex]
where Z=1
I got [tex] R= 10967978.99 m^{-1}[/tex]
then to calculate the electron mass i use the formula
[tex] R=R_{\infty}(1-\frac{m_{e}}{M})[/tex]
where R - the theoretical value of the Rydberg constant
[tex]R_{\infty} [/tex] is the calculated one
[tex] m_{e}[/tex] is the electron mass
M- is a unit mass [tex] 1.66\cdot10^{-27}kg[/tex]
I solve the equation to obtain [tex] m_{e} [/tex] and I get:
[tex] m_{e}= M-\frac{RM}{R_{\infty}}[/tex]
but after plugging in the corresponding values I get
[tex] m_{e} = 1.6598\cdot10^{-27}kg[/tex] which is not correct...If i compare the calculated value with the theoretical...which should be [tex] 9.11\cdot10^{-31}[/tex]
Can someone tell me where do I make mistake? How to solve it?
[/b]
Table 8.6 shows the relative masses of the electron and a number of light atoms is derived from the values of the Rydberg constant (I have uploaded the table)
http://img833.imageshack.us/img833/645/namnlssm.jpg
Turn the problem around and use the data inte last column [tex] \lambda_{12}[/tex] (means) to find the mass of the electron given that the mass of the atoms are exact multiples of the unit mass [tex] 1.66\cdot10^{-27}kg[/tex]
Homework Equations
I have started with calculating the Rydberg constant and used the formula
[tex] \frac{1}{\lambda}=R \cdotZ^2(\frac{1}{(n_{1})^2}-\frac{1}{(n_{2})^2})[/tex]
where Z=1
The Attempt at a Solution
I got [tex] R= 10967978.99 m^{-1}[/tex]
then to calculate the electron mass i use the formula
[tex] R=R_{\infty}(1-\frac{m_{e}}{M})[/tex]
where R - the theoretical value of the Rydberg constant
[tex]R_{\infty} [/tex] is the calculated one
[tex] m_{e}[/tex] is the electron mass
M- is a unit mass [tex] 1.66\cdot10^{-27}kg[/tex]
I solve the equation to obtain [tex] m_{e} [/tex] and I get:
[tex] m_{e}= M-\frac{RM}{R_{\infty}}[/tex]
but after plugging in the corresponding values I get
[tex] m_{e} = 1.6598\cdot10^{-27}kg[/tex] which is not correct...If i compare the calculated value with the theoretical...which should be [tex] 9.11\cdot10^{-31}[/tex]
Can someone tell me where do I make mistake? How to solve it?
Last edited by a moderator: